What’s Wrong with Stuart Armstrong?

Many describe third place teams in the Champions League groups “parachuting” into the Europa League. If we apply this metaphor to Celtic’s performance in their final Champions League group match against Anderlecht, the Celtic plane suffered some turbulence before the crew ejected and headed into the Europa League and Stuart Armstrong was the drunk pilot doing shots of whiskey before take off.

Overly complicated metaphors aside, Stuart Armstrong’s performance in the first half at home to Anderlecht had many Celtic supporters ready to move on from the midfielder. Armstrong is coming off a season last year where he was seemingly the first name on the Celtic team sheet, getting call ups and starts for the Scottish National team, and even leading the Tartan Army to victory (albeit too little too late for the World Cup). Armstrong finished the SPFL season 13 goals and 6 assists, good for a 0.79 Goals + Assists per 90 minutes.

However, as this season began and the good feeling surrounding the well quaffed Happy Armstrong.jpgmidfielder started to fade away. Armstrong was on a contract that expired at the end of the season and seemed to be an impasse on a new agreement. Though a one year extension was eventually agreed to, as fans sometimes do, Celtic supporters were not too pleased with a player who seemed to be looking for greener pastures.

This feeling, combined with a reduction in goals and assists has only furthered the belief among some Celtic supporters that Stuart Armstrong is now surplus to requirements. Indeed, Armstrong is on the score sheet less, scoring only 1 goal and 3 assists so far in league play, 0.49 Goals + Assists per 90 minutes in the SPFL. These numbers have some Celtic fans asking, “What is wrong with Stuart Armstrong?”

And the answer to that question is “Nothing, thanks.” We can expand upon that answer and add a “regressing to the mean”. If you are here, you are likely at least somewhat familiar with the advanced stats in football and that they may tell us more about a players performance compared to traditional stats. While Armstrong may not be hitting the heights he did last season in goals and assists, what do these underlying stats such as xG, xA and others say?

If we first compare expected goals for Stuart Armstrong, we do see numbers that have gotten worse so far this season. Last season in 2,168 minutes, Armstrong had an xG per 90 minutes of 0.33. If we compare that to this season, we see a decreased xG at 0.12 per 90 in 818 minutes. It seems so far that the midfielder is no longer the goal threat he was last season.

Armstrong Goals and xG Graph.png
Since last year, we see Armstrong’s goal scoring come closer to his xG

However, we might need to dig a little deeper into these shot numbers. First, let us address the elephant in the room with Armstrong’s xG numbers last year. Despite putting up very impressive numbers, Armstrong overachieved his xG numbers in his goals scored, scoring 13 goals with an xG of 7.90. Now, some players are able to consistently able to over-achieve their xG over multiple seasons, but so far this season it seems Armstrong is not showing he is able to do that.

Of course, it is still too early in the season to come to widespread conclusions, however there is no shame for a central midfielder not being able to continuously finish at that high of a rate. With his xG total at 1.02 and 1 goal scored, Armstrong is about at where we would expect. In addition to perhaps seeing a regression to the mean scoring goals, Stuart Armstrong has also found additional competition for spots in the Celtic midfield.

While Armstrong was not around the Celtic first team until this time last season, Action Stu.jpgfrom that point on it seemed he was one of the first names on Brendan Rodgers team sheet. However, this season we have seen the emergence of Callum McGregor, goal scoring threat, as well as Oliver Ntcham’s arrival. McGregor has contributed 5 goals already this season in league play, while Ntcham has also added 3 goals.

This competition has seen Armstrong playing less. Last season, Armstrong appeared in 63.39% of available minutes in league play, while this season he has only appeared in 54.37% of available minutes. He has seen a slightly reduced role so far this season, but while he has not been able to score as much for Celtic this season, he has contributed to the attack other ways.

While Armstrong might be seeing some regression when it comes to goal scoring and xG, his passing numbers suggest he is at a similar if not better level than he was last season. Last season, he averaged 0.24 xA per 90 minutes, while this year he is averaging 0.29 xA per 90. He averaged 1.79 Key Passes per 90 minutes (or passes that lead to a shot), but is averaging 2.4 this season. All of this has lead to a similar Assists per 90 minutes for Armstrong as last season, averaging 0.37 per 90 this year compared to 0.42 last season. He is setting up his teammates just as well when he is playing, he is just seeing them converted at a slightly reduced rate.

Stuart Armstrong Pass Map.png

Along with stats showing how he sets up shots, Armstrong also seems to be just as vital in Celtic’s attack overall as he was last season. Looking at xSA, which quantifies the pass before the pass before the shot, Armstong is averaging 0.17 xSA per 90 minutes this season, while last season he averaged 0.07 per 90. This is another metric showing Armstrong has been more than a great head of hair this season.

Armstrong Assists xA.png
Armstrong’s xA and assist numbers have stabilized and remained consistent.

Tuesday night was a rough night for Celtic and their supporters. There is no hiding that Armstrong had a poor game and was subbed out because of it. This game seemed to be the final piece of evidence for many Celtic supporters that Armstrong has regressed and is no longer necessary. However, over this European campaign, who DID have good performances? Ntcham seemed to do much better than Armstrong at home against Anderlecht and set up goals in Belgium, yet his passing was erratic before those goals. The list of Celtic players who get a passing grade in Europe this campaign is a short one and casting Stuart Armstrong aside because of a small sample against superior competition seems short sided.

Yet, Armstrong still seems destined for pastures new soon. He added a year to his contract, but will find himself on an expiring contract at the start of next season. While he his stats suggest a player still able to create for his teammates, we might not be able to expect a double digit goal total from him every year. If Celtic were to get in offer in January or in the summer that is near their valuation of him, it might be wise to sell. If someone offers a transfer sum for a goal scoring midfielder for Armstrong, I would certainly take that offer.

This article was written with the aid of StrataData, which is property of Stratagem Technologies. StrataData powers the StrataBet Sports Trading Platform, in addition to StrataBet Premium Recommendations.

B.U.R.L.E.Y. Adjusts His Predicted SPFL Table

It seemed like a good time to check in with B.U.R.L.E.Y. and see how he sees the SPFL Premiership table shaking out, mostly because a few people asked me and I had time to update everything. If you are wondering what exactly B.U.R.L.E.Y. is, let me direct you to this link where I describe my SPFL projection model and his picks for this year. Before we get to who B.U.R.L.E.Y. sees going down and who will be in the top six, let me first point out that B.U.R.L.E.Y. has correctly picked 3 matches more than both FiveThirtyEight and you dopes. Go ahead and picture a robot with Craig Burley’s head scoring a goal, doing a front flip, and then completing a 20 yard knee slide to the corner flag.

Burley Crowds 538.png

Now that we have that out of the way, let us dive into how B.U.R.L.E.Y. sees each SPFL club finishing. First, I would like to note that the projections go through 33 matches this season, right up to where the league splits in half. The last column is the points per game B.U.R.L.E.Y. projects each team to have through 33 matches multiplied by 38. It is not perfect, but neither is playing 38 games with 12 teams in the league, so here we are.

BURLEY Projected Table

B.U.R.L.E.Y. probably will not get much credit for picking a Celtic-Rangers top 2, but B.U.R.L.E.Y sees the big Glasgow clubs separating themselves from the rest of the league. The top six according to B.U.R.L.E.Y. is a bit more interesting, with Aberdeen, Hibs, Motherwell, and Hamilton (??). St. Johnstone and Hearts are projected to finish in the bottom half, with Partick Thistle projected to go down and Ross County in the relegation playoff spot. Will B.U.R.L.E.Y. get these picks right or will some club go and stick in the robot’s eye? As some cliche spouting coach of something that I forget the name of said, “that’s why you play the game.”

Scottish Football Graduating to “Advanced” Expected Goals

Congratulations Scotland, you have passed Intro to Expected Goals and are now movingProfessor.jpg onto the advanced class. Most following me know that expected goals are the likelihood that a goal will be scored on a shot. Expected goals is now a term that more and more Scottish football fans are familiar with, understand, and can discuss coherently. Sure, there is the occasional “Yer Da” still yelling about “Goals and Points being the only stat that matters!”, but compared to three years ago, football analytics literacy has grown considerably in Scotland.

However, now that many have the basics down, we need to have a talk about expected goals. On Twitter last week, I noticed there was discussion about the usage of xG and in particular summing xG totals for individual matches and saying things like “(this team) should have scored 2 goals because they had an xG of 2.” Let me first throw myself at the mercy of the metaphorical court, I have created a few different visualizations where a summed xG total for an individual match was present. It is still on the xG maps I publish each week for the SPFL.

I chose to sum xG on the graphics I have posted to try and ease Scottish football fans into xG. With that being said, there are some issues with summing xG for individual matches. Danny Page covers the issues in an article he wrote pretty comprehensively. Danny points out that if you sum the xG, you will miss on on the variance that can occur in a single match. In his article, he says:

Arsenal won 0–3 with a xG scoreline of 0.39–1.49. In these cases, some may say “The right team won” because the xG and real life scorelines match. However, these values are only adding expected goals. But something is missing. Only adding independent probabilities misses half of the story: variance.

A good situation to think of here is a shot with an xG of 0.05. That shot may go in, it has gone in before, but it is not likely. The instances where it does go in is the variance Danny is talking about, but generally it is not a shot that is going to lead to goals often. But let’s say that a team has ten of those 0.05 xG shots, compared to a team that has one 0.50 xG shot. The second team’s shot is much more likely to go in than any of the first team’s shots, but summing the xG in this situation they would both have an xG total of 0.50.

Ross County Motherwell Prob 11_4_17
The xG graphic that will be out each week for match, borrowing heavily from Danny Page and his xG simulator.

Sometimes those lower xG shots will lead to a win, thus the idea of variance. Typically  summing xG over the course of a season variance usually will find the mean. However, anything can happen in one game. Therefore, Danny puts forth that rather than summing xG totals in a single match and making conclusions off that, it would be better to use win percentages based on the xG of each team’s shots and the likelihood of the goal difference for that match based on the xG output, so that is what we are going to do.

 

To do this, we will take the xG of each shot for a team in a match and run them in a Monte Carlo simulation 1000 times. This is similar to what I do to come up with the numbers for B.U.R.L.E.Y. for the season. With these simulations, we can come up with 1,000 results of matches with the xG results of a particular match and produce how many times each team would typically win and draw, what would be the most common scoreline, and the typical points per game from that xG performance. In addition to seeing the sum of the xG for a match, we will see the team that was most likely to win and what the score would typically be from a match with that xG output.

St. Johnstone Celtic Prob 11_4_17.png
My xG graphic for St. Johnstone v. Celtic on November 4th.

Using Danny’s xG simulator and taking all the graphics he came up with as a template, I will now be producing these graphics for every SPFL match. Henceforth, these graphics will accompany the xG maps we have been producing each week and will hopefully give some further insight into expected goals. As this now the “advanced class”, please feel free to let me know if you have questions or comments about this!

This article was written with the aid of StrataData, which is property of Stratagem Technologies. StrataData powers the StrataBet Sports Trading Platform, in addition to StrataBet Premium Recommendations.

Team Effort the Reason for Motherwell’s Fast Start

The past few years have been a bit of a roller coaster for Motherwell Football Club. Over the last five years, Motherwell have finished ninth, fifth, eleventh, second, and second.Edinburgh City v Motherwell, Betfred Cup Group F, 25 July 2017 While the years of European qualifiers are not that far off, the results at Fir Park have not been as successful lately, including a relegation fright in 2015 when they finished in the relegation playoff spot and had to beat Rangers to keep their Premiership status.

However, this year has started off much differently for Motherwell. While a second place finish similar to the years Stuart McCall led the club might be a bit too much to ask, the Steelmen sit in fifth place in the SPFL Premiership as of writing and have a League Cup final to look forward to. A top six finish would seem to be the expectation now this season for Motherwell. While a good spot in the table is always nice, we know that sometimes the table lies to us and we need to look deeper into the corresponding numbers behind a team’s performance.

SPFL League xG Difference_Goal Difference.png

There is good news when we look at the underlying numbers for Motherwell thus far, we see the stats match their good start. Motherwell have an xG of 13.45 and xG against of 9.30 for a xG difference of 4.15, which is 5th best in the league through 11 matches. These underlying numbers suggest that if the Steelmen can continue that type of performance, they can not only hope for a top six position in the table, but also start to possibly dream about a European adventure again.

It has taken a few years for it to happen, but Louis Moult has finally become a household name among football fans in Scotland. For TheTwoPointOne towards the beginning of this season, I wrote about Moult’s great season last year, but Motherwell needing to find some help on the attack after losing partner Scott McDonald this offseason. Last season, Moult helped carry Motherewell, putting up 15 goals and an xG of 10.74 or 0.35 per 90. This year he is back to putting up good numbers again this season, with 5 goals (3 non-penalty goals) and a non-penalty xG of 3.63, which is 5th in the league.

Moult Bowman.png

Moult seems to be in good form again this season, but he is getting some help from his teammates and that seems to be making all the difference for Motherwell. Before the season started, there were questions who would be taking McDonald’s place as the other Motherwell striker, but Ryan Bowman has stepped up to that role in the first part of the season.

Bowman has matched Moult’s 3 non-penalty goals, with a xG of 2.24 and 0.26 per 90 thus far. While Moult gets lots of shots, ranking 2nd in the league in shots overall and 3rd in shots per 90, Bowman has been able to get good quality shots despite not having the same quantity of shots as Moult, averaging 0.19 xG per shot, which is 7th best in the SPFL, and 66.67% of his shots occur in the danger zone. Will Bowman be able to continue to keep scoring off of such good quality shots as defenses in the league realize they need to account for him? Motherwell’s success may hinge largely on it.

Cadden

Both Moult and Bowman have surely enjoyed the play of young Chris Cadden on the wing for Motherwell. Cadden just recently received a well deserved call up to the Scotland U21 squad (and I contest perhaps should have been called up to the main squad) and has been impressive so far this season. He has 21 key passes so far (2.1 per 90) and a xA of 3.06 (0.2 per 90), which are both 3rd in the league this season. Compare this to the Motherwell squad last season, where no one at Fir Park finished among the top 20 in the SPFL in xA or key passes.

Cadden has only 1 assist this season, which might hint his teammates have let him down a bit, but his passing creativity is clear to see in the numbers and on the pitch. Not only are his key pass and xA numbers impressive, Cadden also has an xSA (expected secondary assist) of 1.11, which is 19th in the league. Cadden has been vital to Motherwell’s potent attack this season and the Steelmen will be relying on him to continue this the remainder of the season.

While the likes of Ryan Bowman and Chris Cadden have helped Louis Moult and Motherwell put out a strong attack on the Fir Park pitch, last season the club actually had a decent attack as well. In 2016, the ‘Well had the 5th highest xG at 56.09. What was not decent for them was their defense, ranking dead last in the SPFL in xG conceded at 74.34.

Key Entries Against_xG Against.png

This year has been a much different story for the Motherwell defense though. Through 11 matches, the club has the second lowest xG against in the SPFL at 9.30. Only Celtic has allowed a lower xG against thus far, as in the team that has not lost in 62 domestic matches, so pretty impressive company. If we look at the number of Key Entries allowed, or any ball that is played beyond the 18 yard line by the opposition while defending, Motherwell has allowed 222 so far, with only Celtic, Hibs, Aberdeen, and Rangers allowing less. Comparing the key entries against to xG against in the SPFL this season, we see a decent relationship, so this number will be interesting to keep track of as the season unfolds.

With such poor numbers last season, Motherwell clearly had to make a change in the back. Enter Cedric Kipre, Charles Dunne, and Peter Hartley. Stephen Robinson has deployed theseKipre.jpg three either in a back three or part of a back five in recent matches and the results speak for themselves. Both Kipre and Dunne were brought to the club on free transfers, while Hartley was brought on loan from Blackpool, though his contract expires in May of 2018. Dunne and Kipre are younger players at 24 and 20 respectively, while Hartley has more experience at age 29. These additions have turned Motherwell from the worst defense last season to one of the best this season. Furthermore, they show that SPFL teams can help turn around part of their team with some shrewd signings.

Last season, Motherwell heavily relied on Louis Moult. Their defense was a shambles and besides Scott McDonald, the attacking burden fell mostly on Moult. But so far this year, it has been much more of a team effort at Fir Park. The club no longer has to rely on Moult to win. If they can continue to get these same types of contributions from Bowman, Cadden, Kipre, Dunne, and Hartley, a top six finish should be the minimum expectation for Motherwell.

This article was written with the aid of StrataData, which is property of Stratagem Technologies. StrataData powers the StrataBet Sports Trading Platform, in addition to StrataBet Premium Recommendations.

A Statistical Preview of Celtic’s Champions League Opponent RSC Anderlecht

Going into match day 2, Celtic could not have a more different Champions League opponent in RSC Anderlecht that match day 1 foe PSG. Like Celtic, Anderlecht were seen as the also rans in the group also featuring mega-bucks squads Bayern Munich and Paris Saint Germain. It was all but assumed Celtic and Anderlecht would be fighting for third at the end of the group, and Anderlecht also was on the wrong end of a big loss (though not as big as of a loss as Celtic) to Bayern Munich in their first Champions League match of the campaign.

Unlike Celtic, things have not gone so well for Anderlecht domestically back in Belgium. onyekuru.jpegThrough eight matches, the reigning Jupiler Pro League champs sit in seventh place, 9 points behind Club Brugge. While this position may spell curtains for teams in other leagues, the Belgian set up allows for some hope. The top 6 teams in the league advance to a playoff. In the playoff, each team has their point total halved and then they play each of the top six teams twice more. The club with the most points at the end of that is the Champion.

While the unique Belgian league set up allows for a team to have hope after a slow start, it was not enough for the powers that be at Anderlecht and after seven matches manager Rene Weiler was sacked. Weiler led the club to the title in his first season last year, but only picking up 2 wins in those first seven matches was not enough for those at the club. While the club struggled to get results under Weiler this season, what do the underlying statistics say about Anderlecht’s performance thus far? Luckily, the fine folks at Strata can help us find out (as well as teach me that there is a club in the Jupiler Pro League that has “excel” in it’s name, a stat nerd’s dream team!)

Sheet 2-2

Looking at the numbers for the Juplier Pro League, we see stats telling a different story than points in the table are telling us for Anderlecht. In fact, Anderlecht’s underlying stats have been fairly good so far this season. Anderlecht has the best xG difference, the 2nd best xG for, and the best xG against through seven matches in the league. The Purple and White have conceded the lowest number of shots and have the highest xG ratio in the league (the ratio of xG for/xG+xG against). The only numbers that are not so impressive for the club is their goal total at 8, their goal difference at -1, and their points at 9.

Dashboard 1-3

These numbers suggest that Anderlecht could be due for some positive regression to the mean, in which their performances start to result in more goals and points on the table. They also suggest maybe the club should have been more patient with Weiler, as the performances were OK despite Anderlecht being on the receiving end of some bad luck. With Nicolas Frutos, David Sesa and Thomas Binggeli are taking over managing the club on an interim basis, will the club see that positive regression that the stats say their performances deserve or will the sacking throw the club into disarray and see performances worsen? Hopefully for Celtic, it will be the latter.

Anderlecht Goals.png

Taking a look at where Anderlecht’s goals have come from domestically, a pretty clear pattern emerges. Five of Anderlecht’s six league goals in their first seven matches came from the area we like to call the danger zone, where you are more likely to score. On the other end of the ball, seven of nine of their goals conceded came from the danger zone they were defending. Furthermore, five of nine came from crosses, but only one from a header. To me, this screams out a weakness that Kieran Tierney can exploit. Tierney is wonderful at bombing down the wings and making a killer cut back low cross. This sets up his teammates for this high probability danger zone shots. Seeing as this seems to be something Anderlecht is susceptible to and is a strength of Celtic’s, one would think this is something Celtic will need to exploit to be successful Wednesday.

xG Leaders Belgium.png

If we look at some individual players Celtic will need to look out for, a few names pop up on the Anderlecht squad list. Henry Onyekuru and Lukasz Teodorczyk are tops at the club in goals and expected goals, and seventh and eighth in xG in the league respectively. Everton loanee Onyekuru, who says he turned down a move to Celtic this summer, has 3 goals, an xG of 2.75, 0.61 xG per 90, and 3.3 xGAS, while Teodorczyk, the £4m signing from Dynamo Kyiv, has an xG of 2.59, 0.44 xG per 90, and a 4.26 xGAS. These two have been Anderlecht’s most high potent attackers domestically, though neither started their last match against Waasland-Beveren, though Onyekuru came on as a sub at half.

xSA Belgium.png

Looking at some xA numbers, Teodorczyk has the highest expected assist numbers at the club and is twelfth in the league at 1.52. The man who is pulling the strings for the Anderlecht attack has to be Sofiane Hanni. Hanni has the highest expected secondary assist total at the club and is second highest xSA total in the league at 1.87. Hanni isHanni usually deployed as an attacking midfielder centrally and is the linchpin to the Anderlecht attack that has yet to find the goals, but has underlying numbers that suggest they are on the verge of being unleashed.

While it is hard to speak about the Belgian press, even the most ardent Celtic supporter probably understands it is a race for 3rd place after the 5-0 loss to Paris St. Germain in match day 1. To finish third and see European football past Christmas, Celtic probably need at a minimum of four points from their two matches with Anderlecht. The Purple and White may have struggled domestically thus far, but their underlying numbers suggest their is a good squad in there. Will Anderlecht rebound after Rene Weiler’s sacking? It is hard to guess, but Celtic would be wise not to take them for granted.

This article was written with the aid of StrataData, which is property of Stratagem Technologies. StrataData powers the StrataBet Sports Trading Platform, in addition to StrataBet Premium Recommendations.

Alfredo Morelos: Some Quick Praise from a Small Sample

I can assure you there will no tired/borderline racist cliches in this article about Alfredo Morelos. Last season, Rangers had the second highest expected goal total in the SPFL, yet finished third in the table. Whether that is due to bad luck or poor finishing can be debated, but as a result Pedro Caixinha and Rangers decided that they needed to upgrade at striker. Out went Martyn Waghorn and Joe Garner and in came Alfredo Morelos from HJK Helsinki. Last season, Morelos scored 20 goals in all competitions for the Finnish club, but could he continue to score goals in the step up to the SPFL?

Morelos.png

Through six games, Morelos has certainly answered that question with a resounding “yes”. Going into the match-up with Celtic, the Colombian is currently top the goal scoring table in the SPFL Premiership with 6 goals. In addition to having the most goals in the league, Morelos has the highest xG in our model at 3.61, which is 0.77 per 90 minutes and 0.23 per attempt.

Looking at these numbers and his shot map above, it is easy to see why Morelos has had early success with Rangers. the Colombian striker has been able to get into great positions and get off shots with a higher than average scoring probability. 63% of Morelos’ shots this season have come from the Danger Zone, or the area in the box between the ends of the 6-yard box. All but one of his shots have been inside the box thus far. Morelos clearly thrives inside the box, getting shots where they can do the most damage.

SPFL xG leaders

If we compare Morelos’ per 90 numbers for xG to Moussa Dembele’s from last season (0.69 xG per 90), they are similar. Of course, it is way too early to declare Morelos on the same level as Dembele, but if the Colombian striker can continue his output at this pace it would not be unreasonable to compare the two. However, even if Morelos can reach the same rarefied air that Dembele did last season, Rangers still may need someone else to help ease the burden on “El Bufalo”.

Besides Morelos, Josh Windass and Kenny Miller are both among the top 20 xG leaders in the SPFL that are on Rangers. Yet, between Miller and Windass, they haveMorelos 3 1 league goal between them. Morelos may have the talent to carry Rangers for a period of time, but like all players, he could find himself out of favor with the finishing fairy and not find the net for a few matches. If Celtic are without Moussa Dembele, as they have been up until recently, they have the likes of Scott Sinclair and Leigh Griffiths that can help knock in goals. Can Morelos’ Rangers teammates provide the same support? It has yet to be seen.

While six games is a small sample in which we do not want to jump to conclusions, it certainly seems Rangers have upgraded significantly in the striker position from last year with Morelos. With such fine play, the Colombian striker is already subject to transfer rumors. However, if Rangers can hold onto him all season, they can expect to see greatly improved fortunes in front of the goal from last season.

This article was written with the aid of StrataData, which is property of Stratagem Technologies. StrataData powers the StrataBet Sports Trading Platform, in addition to StrataBet Premium Recommendations.