Alistair Johnston's Celtic right-back role change assessed

He was on the end of a nasty ankle injury before the end of last season and therefore missed a good chunk of preseason. He did not return to first-team action until August 26 and was eased back in with two appearances of around an hour. Since then, he has been virtually ever-present apart from a partial rest at Hibernian and a full one away at Ross County.

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When I considered this topic, I went straight to the StatsBomb on ball value summary, and was rather taken aback by my findings…

OBV

StatsBomb’s signature aggregated metrics on ball value evaluate all actions with the ball in terms of their value to the team broken down into five categories.

Comparing Johnston this season and last was a little surprising.

Johnston was a real standout in the SPFL last season, ranking 94th percentile for passing, 84th for defensive actions and even 62nd for shot on-ball value. Overall, his OBV was 85th percentile.

This season his overall OBV is down only one notch to the 84th percentile and the same by value (0.28) but he is now in the 2nd percentile for defensive actions. Although his passing seems to be near the best in the league.

All quite odd.

Role

An obvious place to start is whether his role has appreciably changed. Under Ange Postecoglou, we heard a lot about inverted full backs and seeing both Johnston and left-sided colleague Greg Taylor in central midfield supporting Callum McGregor became no big surprise.

This has been less evident under Brendan Rodgers but let us compare this and last season’s heat maps covering league games only.

The main differences are indeed less coverage inside the field across the part but especially near the halfway line where the full backs tended to invert to create a second line of transition defence with McGregor.

There is slightly heavier red activity nearer his own goal and slightly less in the final third probably both reflective of a lop-sided first set of SPFL fixtures in terms of difficult away games and slightly more comfortable home games.

A slight evolution then, but enough to explain the defensive numbers?

Defending

Johnston’s total defensive actions are only slightly down on last season with 10.62 versus 10.1 per 90 minutes last term. What is striking is he is down on winning tackles, aerial duels, and interceptions outright.

His overall defensive action success rate is static at 62 per cent. Yet his overall possession won from defensive actions is down markedly from 77 per cent to 63 per cent.

This means that broadly Johnston is being just as successful in his success in duels, but that the ball is not being won by Celtic nearly as much as a result.

Taylor’s equivalent numbers are not down nearly as much – his possession won from defensive actions is slightly down from 62 per cent to 61 per cent.

Consider also that Johnston’s possession win percentage of 77 per cent is the highest I have ever recorded for a full back apart from Mikael Lustig in 2017-18 and 2018-19. The next highest is Hatem Abd Elhamed on 76 per cent in 2020-21.

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The commonality between all three is that they all are equally comfortable at centre back and indeed it could be argued all three prefer the right side of a back three. That is certainly Johnston’s usual position for the Canadian national team. All three tended to tuck in on occasions depending on where the ball was.

Back to Taylor. Johnston’s full-back companion is still inverting to a much greater extent in comparison to the Canadian. Could it be, simply, that by playing more to the touchline as per a traditional full-back, many of Johnston’s duels result in opposition throw-ins given where the ball may end up versus when he was inverted more, there was a higher chance the resulting ball would end up at the feet of a fellow Celtic player?

I can’t say, but that seems a logical working assumption for now.

Indeed, according to StatsBomb, Johnston is far more involved in pressing and counter-pressing this term, again maybe a feature of more traditional full-back play.

Across the board, he seems to be more aggressive in his off-ball actions and like the whole Celtic team his average defensive action distance is now over 44 metres from his own goal (it was 40.5 last season). Being closer to the opposition is allowing more counter-pressing opportunities.

Indeed, his total number of ball recoveries per 90 minutes is up markedly from 9.7 to 11.5 per 90 minutes. That is probably a feature of Celtic’s more aggressive defensive positioning rather than any change to his positioning under an inverted full-back regime.

Creating

In general, Johnston is completing ten fewer passes per 90 minutes from open play (down from 64 to 54) whilst giving the ball away at the same rate (10 loose passes). Therefore, his overall pass accuracy is down from 86 per cent to 84 per cent.

Most markedly his pack passing numbers are well down on last season. He averaged 14.4 pack passes per 90 minutes with an average packing score of 82.23. This season that has dropped to 9.07 with an average pack passing score of only 55.21. His average pack receiving score is also down from 46.4 to 34.9 meaning he is not getting into advanced positions to receive the ball as much.

In general, he is showing less attacking intent than last season with touches in the opposition box down from 2.23 to 1.5; danger zone passes down from 0.78 to 0.39; successful crosses down from 0.41 to 0.32; and overall chances created down from 1.24 to 0.95.

Is this poor form, different usage or a function of a tough opening start to the season (the above data all included Champions League ties), or other?

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Could it simply be the outworkings of the transition from highly aggressive vertically focussed “Angeball” with an emphasis on telling direct forward passes? Now can we see more control and the keeping of possession with the ball being recycled rather than thrown forward, especially in the European arena? This would certainly impact the full-backs who are the first line of attacking passing in many cases.

The overall drop-off in Johnston’s creative output is certainly noteworthy and we will need to wait and see whether this is a hangover from his summer injury troubles. Or, whether Rodgers’s more possession-based football is perhaps stymying some of the creative talents that players like Johnston possess.

A complex tale, this one, but my concluding thoughts are that perhaps we are not getting the best out of Johnston if his marauding full-back tendencies are not fully unleashed. Meanwhile, Rodgers is getting different but equally effective defensive performances from his Canadian full-back.