It has been a ragged season for Celtic in many respects, not least the changes to personnel due to injury, as well as the failure to replace experienced and talented leavers.

Throughout the early part of the campaign, one unequivocally bright light was Danish internationalist Matt O’Riley. He seemed to relish a freer role under Brendan Rodgers, less bound by well-rehearsed attacking patterns scripted by previous supremo Ange Postecoglou. Both the warmer, more personal, managerial style of the Irishman and the freedom O’Riley had to follow his instincts on the pitch combined to release a run of form that was a rare constant in Celtic’s season.

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By the start of January, the midfielder had scored 10 goals although only one has followed since a 3-0 victory in Paisley. He has an incredible 17 assists, seven more than Luis Palma. 28 scoring contributions is eight more than Kyogo Furuhashi. This despite being a more rounded midfielder than under Postecoglou.

He is simply more involved and integral to how Celtic play, all over the pitch. Yet, despite this, when transfer rumours surfaced in January about interest from Spanish giants Atletico Madrid, there are some within the support who detect a drop off in O’Riley’s performances after that.

Had the midfielder's head been turned, has his form dipped due to fatigue – he completed 22 consecutive 90 minutes from November to March?

Season comparison

With Aaron Mooy being replaced with younger players learning their trade (Paulo Bernardo and Odin Thiago Holm) and Reo Hatate largely being unavailable all season, the burden of supporting Callum McGregor in the midfield engine room has largely fallen to O’Riley.

We’ve seen the outworkings of that in sheer on-pitch involvement above. As per the SPFL data, by comparison, StatsBomb’s midfielder radar shows this:

The green is this season. O’Riley has already completed more minutes in the league than last season. The radar is a little contradictory in that the volume of tackles, interceptions and pressures has decreased from last term, yet the quality as measured by defensive on-ball value, has improved.

Otherwise, he is broadly as creative as last term with the same weakness of not being a heavy ball carrier. Assisting others is his sweet spot being in the 97th percentile, closely followed by overall passing on-ball value in the 85th percentile. The question remains, has he regressed as the season has progressed?

Season trends

I can break down O’Riley’s contributions using some aggregated data - whilst reductive - if we consider the trend lines over the season, we can directionally see whether the form is ‘improving’ or not.

The defensive actions success rate is what it says on the tin. It measures the percentage of times a challenge, interception or other defensive move is successfully won.

This is quite a spiky view as defensive actions are not high volume and so there is a high degree of variance from match to match. The orange line shows the trend over the season which in this case is downwards from high 50’s to low 40s in percentages.

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Counterintuitively, given that Celtic are now out of Europe and the early part of the season would include Champions League matches, this makes some sense when you consider that in those much tougher fixtures, O’Riley was executing far more defensive actions. As the season has progressed the average ‘difficulty’ of fixtures has eased somewhat leading to less defensive action. However, this trend does support the ‘regressing’ hypotheses.

Let’s consider ball progression. Packing encompasses forward passes given and received as well as forward dribbles plus winning and losing possession leading to either teammates or opponents being wrong side of the ball.

O’Riley’s overall packing score is around the 100 mark but has reduced over the season, slightly. It seems a pretty consistent performance to me but being statistically pure, the trend line is downwards, so are the critics justified? O’Riley’s start of season goal rush was remarkable, so let’s consider expected scoring contribution – expected assists plus expected goals per 90 minutes.

Last season was a standout for O’Riley in that his actual goals scored (four) trailed his xG so spectacularly (10.65). And - despite his goals tally slowing post-New Year - his overall expected scoring contribution is trending upwards.

This can also partly be explained as above whereby the relatively easier non-European fixture list will tend to allow for this. That is, it will be easier to create and have chances against SPFL opposition than Champions League opponents. You can see that in the trend whereby the early part of the season sees peaks and troughs that are relatively more extreme than the recent months against more similarly capable opponents.

Overall attacking threat score covers a wide range of final-third activity from entries into the box to the number of shots. Here is O’Riley’s trend for overall attacking threat:

The average has moved up from around seven to nearer 12 CAT score per 90 minutes. Whilst there was a dip around February time, his attacking threat has been consistently high in the last four matches.

Summary

Overall, there is no conclusive evidence that O’Riley’s form over a range of performance metrics has seriously declined over the season. In large part, he is showing admirable consistency. Variation seems more to do with the quality of opposition which would probably hold for most players.

In O’Riley’s first two seasons under Postecoglou, he was seen as a young player and would often see bench time whilst the likes of Hatate, Mooy, David Turnbull and Tom Rogic were selected. This season - given the leavers and the stricken - the Danish international is now an integral part of Celtic’s team. When Postecoglou’s all-conquering side of last season was in full flow, a relatively quiet O’Riley performance would have gone largely unnoticed providing Mooy was pulling strings or Hatate was providing magic moments.

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This season we notice that O’Riley is relatively quiet. He is so crucial to Celtic being the mainstay and constant in the ever-changing lineup. O’Riley has developed but not as much as our expectations of him given his more prominent role in the team.

He may well move on in the summer, but I cannot see compelling evidence that is affecting his Celtic performances. On the contrary, he has been the beating heart of this team in a transitional season.