The Celtic statistical proof that Liam Scales has improved

This a leading question but one the lads answered in the positive as regards the level of consistency that Scales is now showing and how he is now a first pick for club and country. Cameron Carter-Vickers’ persistent foot injury and new signing Auston Trusty still within his ‘settling in’ period, allied to ongoing doubts as to the trust Brendan Rodgers places in Stephen Welsh and Maik Nawrocki, has seen the 26-year-old Irishman become the defensive mainstay this season.

He is at an age where most players are considered at their “peak”. That is the confluence of optimal physical capability and job experience. For Scales, that may be a year or two ahead as he has only been a regular at Celtic for just over one season, and also his international selection has been secured over the last year. Calm and unflappable, Scales has never been anything but phlegmatic about his role. The notion he may suddenly be replaced as the first choice at Celtic outside of injury or dramatic form loss seems unlikely.

Let’s see what the data reveals.

Defensive actions

The heavily aggregated defensive action success metric considers every defensive action and calculates the successful proportion – duels won, interceptions won and so on. The range of performance by this metric has always been a narrow one, highlighting the small margins at this level between good and average players.

Anything over 80 per cent is excellent, whilst 75 per cent and below would be poor for the Celtic central defensive peer group. Historically, Scales started in the 75 per cent bracket and performed at that level for most of the 2023-24 season.

Here are his five-match rolling average defensive action success rates (DASR) in all competitions.

Between the beginning of last season and mid-January 2024, Scales had only two matches with a DASR of 80 per cent or over. In January and February, he went six matches with over 80 per cent DASR. It never hit 80 percent again until mid-May when there was another flurry of hitting that benchmark.

This season has seen a 75 per cent average for the first five matches and an 85 per cent average for the most recent five. The overall impact of those trends is that Scales’ DASR trend average started below the lowly 75 per cent but is now over the stellar 80 per cent.

We may expect another dip as the Champions League campaign continues but the trends are encouraging as regards overall defensive performances. The main driver has been better outcomes in defensive duels.

Overall, he is winning 81 per cent of duels versus 77 per cent last season. Those may seem a small difference but represent a significant shift upward when compared to the historical population of Celtic centre backs. Why is this?

Scales has been trusted and may be performing at a higher level of confidence and belief. He is also 26 and allied to his international experience, may be a late flourisher at this level. Also, there is the vastly improved team dynamics after a year under Rodgers. As we saw with Carl Starfelt, individual performance improved alongside the collective coherence of the team.

On ball value

StatsBomb’s signature aggregated on ball value metrics provide insight into passing, defensive actions, shooting, and dribbling and carrying as regards their value added (or subtracted) from a team’s chances of scoring/conceding.

This covers SPFL matches only and is in relation to all other players in the SPFL as opposed to just Celtic peers. StatsBomb detected a slight downtick in defensive action OBV from 0.04 to -0.02. The only metric improved upon is the shot OBV.

Otherwise, he profiles as per last season in comparison to the rest of the league. Given Celtic’s dominance, most of their players feature in the 90th plus percentiles when the focus group is the rest of the league. That can dampen nuance in the data.

Pack passing

A key skill for Celtic centre-backs as the most ball-hungry position in the most ball-dominant team (70 per cent plus possession) is ball progression.

The historical criticism aimed at Scales is the speed of his passing as well as a tendency to play the pass sub-optimally in relation to the physical arrangement of the recipient. Just a bit behind, not far enough away from the would-be interceptor.

We don’t have pass speed metrics, but through pack passing we can assess the degree by which each player gets the ball forwards and takes opponents out of the game. Like DASR, I have plotted Scales’ five-match rolling average pack passing score over the last two seasons.

The start of this season saw pack pass scores of 170 and 142 in the first two fixtures of the campaign. Those contributed to a peak for Scales over the last year. His overall average pack passing score has increased from around 63 to currently 80 in that time. For context, Kristoffer Ajer averaged 30 per season, and Carl Starfelt and Carter-Vickers 53 each over their time.

Scales’s 71.28 is easily the highest pack passing average for any centre-back in my records (back to 2017-18). It took until 2020-21 for anyone to average over 40 (Stephen Welsh). Some of this has to do with team style – Rodgers is a possession-dominant coach compared to even Ange Postecoglou and certainly Neil Lennon.

But still, Scales is setting new benchmark highs for pack passing out from the back. It may not always look elegant and there is still the odd dangerous turnover thrown in (about one per game to be fair). In this key aspect, Rodgers has someone he can trust to keep Celtic playing out from the back. There is no better way forward for a player than to make themselves useful!

In conclusion - Scales IS improving and as he settles into his peak years, he has that left-sided centre-back spot to hold onto.