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.

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.