Carl Starfelt's Celtic improvement is indisputable... but is it enough?

Additionally, fellow TCW columnist James Dailey and I reached a conclusion on an episode of The Huddle Breakdown that Starfelt in particular was so far off what was needed that we could effectively 'call it' on his unsuitability. Not what we wanted to conclude on a £4million-plus signing.

Since then - or, more precisely, since January - Celtic have improved a lot in terms of overall team cohesion and defensive structure and Starfelt has been a regular part of that.

So was I too hasty? Does redemption (and indeed apology from me) follow? Let's find out...

Defensive Performance

This is the view I always use for centre-backs: plotting defensive action success rate against possessions won from defensive actions.

The eye test and data tests generally align despite defending being a difficult thing to measure as it is largely about organisation and shape - aspects which are not solely individual traits.

Here is the updated picture:

The good news is that Starfelt is improving. He has nudged up a couple of percentage points by both metrics and is now flirting with the 'middle class' of recent Celtic centre-backs.

In comparison, Carter-Vickers continues to profile well against the best centre-backs of this era while Welsh has also improved over his previous years’ data.

Defensive Errors

Perhaps the most worrying aspect of Starfelt’s early Celtic career was his tendency for an individual error.

Some of this is structural – getting used to new players and systems and also not having a steady partnership around you with centre-back and full-back – but much of it is down to style. 

Starfelt is what could be termed an 'optimistic' defender.

An optimistic defender always thinks he can win the ball and that the best outcome will occur (this is a great trait in a striker). Consequently, he tends to try to win challenges - both aerially and on the ground - where discretion is really the better option.

This results in him being dragged under the ball frequently or being turned in exposed areas - for instance, centrally 30 yards from goal. Defenders should, as a rule, be pessimists and always assume the worst.

Compounding is his rather odd physical gait. He simply expends too much energy on basic movements thus taking valuable milliseconds. Watch when he has to turn to pass the ball – he is a swirl of arms and legs. It seems a constant battle to maintain balance. Contrast this with the ruthlessly efficient physical movements of his partner Carter-Vickers - the very study in economy of effort.

Having said all that,what has occurred recently is a significant downturn in individual errors from the rarefied downlands of Efe Ambrose/Shane Duffy territory to something more average.

An acceptable benchmark is 0.5 individual defensive errors per 90 minutes. Starfelt is near enough to that for a “well done, big improvement!”.

Why is this? It's not an easy question to answer. As well as the player settling into Scotland, life in general, getting used to the system and obviously having a very steady partner in Carter-Vickers with Joe Hart behind, there is a bit of  'system over personnel' at play here.

What that means is, as the season has developed and Ange Postecoglou has had more time with the team on the training pitch, the defensive cohesiveness of the whole team has improved. What we are seeing is a well-organised team that is perhaps greater than the sum of their parts. It is what good coaches do. Positioning and reactions to danger become well drilled.

My own data collection suggests Celtic have conceded 8.3 xG from open play in 2022. That is 0.52 xG from open play per 90 minutes, which is more than a solid foundation. Yes, there are weaknesses from set-plays but that is improving too (only 2.6 xG in the same period).

So, yes, credit to Starfelt for improving in this regard but the overall team cohesiveness and understanding has helped here.

Distribution

A key attribute for Postecoglou is for all his players to be comfortable getting the ball forward while maintaining overall control and possession. Think of this approach as being a hybrid of Rodgers-ball (possession, possession, possession) and Lenny-ball (more direct). It is a difficult balancing act.

Here’s how the centre-backs stack up in recent seasons:

Again, it's the importance of team style over personnel.

All the current crop of centre-backs are at the top of this distribution for 'pack passing' (forward passes that take opponents out of the game).

While none will surpass Kristoffer Ajer for taking the ball forward with dribbling, the current pairing play almost double the number of forward passes than previous players.

Starfelt achieves a lot of volume in this regard meaning he is good at bypassing the initial attacking press or opposition line and getting the ball to the winger or full-back.

None of this is to suggest Starfelt is a 'great passer', more that he can be trusted to do the job that he is being asked to do.

Under previous managers, centre-backs were more likely asked to get the ball to Brown or one of the full-backs as soon as possible, build from there and take minimal risk in their passing.

In short, the defenders pass forward a lot because that is the job they have been asked to do. The trick is to recruit optimally for that skillset.

Premiership Comparison

Finally, let’s return to StatsBomb data to see how Starfelt is faring versus other SPFL centre-backs:

This is a good example of where care is needed with data. Starfelt is showing as 99th percentile for volume of aerial wins. Great. But a reason for this is that teams in the SPFL often target Celtic’s left side (Greg Taylor and Starfelt) due to perceived aerial weaknesses. Starfelt is only in the 62nd percentile for percentage of aerial duels won - it is one of the weaknesses.

The positive side of his aggressive, front-foot style of defending comes out in being 99th percentile in interceptions and 92nd percentile for ground duels or tackles. His passing is also highly ranked for the reasons already noted above.

Summary

Starfelt must be given credit for improving. All his data points show progression but the main area of joy has been the sharp decline in his individual defensive errors. Those tend to be the eye-catching 'moments' that fans remember.

Much of the overall improvements in Celtic’s defensive team performances are due to robustness of the system and familiarity from the players as well as more consistent selection.

The reason for pointing that out is Starfelt’s fundamental defensive action stats remain low compared to most recent central defenders. There are aspects to his game it is difficult to see changing much – his innate over-optimism; his low aerial duel success; his rather awkward physical movement.

In summary, it is great to see him improving and that Celtic are now looking like a well-coached side. But is there better out there that would fit the system? Yes.

For Celtic to scale domestic performance levels to a European level, they likely need two centre-backs at Carter-Vickers' level to be successful.