Reports from Japan suggest Vissel Kobe left-sided centre-back Yuki Kobayashi is on the verge of signing for Celtic when the next transfer window opens in January 2023.

The 22-year-old is out of contract at the end of that month, according to TransferMarkt, and would therefore be ‘free’ in terms of a fee to his current club. 

In his press conference earlier this week, Ange Postecoglou appeared sanguine about the upcoming transfer window. He suggested that all the planning has been done, and his thoughts have now turned to the summer 2023 window.

‘Lawwell-ball’, as the club’s transfer strategy became known among the fanbase under the previous regime, must truly be dead if that is the case.

But back to the centre-back position. The specifics of Kobayashi as a left-footed, left-sided centre-back adds to the intrigue regarding how the Parkhead side's central defensive unit may shape up in the second half of the season.

With World Cup-bound Cameron Carter-Vickers a lock-in for the right-sided centre-back slot, what does this mean for the array of defenders vying for the left-central defensive position?

It was telling that following a long-term hamstring injury, Carl Starfelt, stellar in the Santiago Bernabeau but rested at home to Dundee United, was recalled for the tough assignment at Fir Park on Wednesday. Last season’s dependable partnership was restored.

That injury, plus similar woes for Stephen Welsh and even the normally durable American international, has led to Moritz Jenz being the most utilised centre-back of the season. 

Signed on loan for a year from FC Lorient, the young German became the latest ‘try before you buy’ acquisition. Apparently a target for some time, the 23-year-old has made no secret of his desire to make the move permanent next summer. 

“I feel I have adapted to Scottish football really quickly,” he said earlier this season. “I really enjoy it here, and I am really enjoying my time at Celtic. I keep saying it, but every day is a dream, and hopefully, it can continue for many, many more seasons.”

Jenz is in the top five for minutes played in the squad so far this season with 1,640 under his belt already. Has that utilisation been down to injury and happenstance or because the German is seen as the future for Celtic?

Let’s see what the data says...

StatsBomb

The StatsBomb data for Jenz covering the SPFL first:

Celtic Way:

In general, players from the top two sides in the league will be in the top percentiles on most measures, given the dominance those sides have over the rest of the league - but there are a couple of snippets here.

Aerial duels are a big part of Scottish football and Jenz is in the low 27th percentile with a 58 per cent win rate. For comparison, Carter-Vickers is 98th percentile for aerial win percentage and 92nd for overall aerial duel wins.

In the Champions League, everything shrinks a bit:

Celtic Way:

The Hoops loanee's aerial win percentage is much higher in this competition, but teams tend not to lump high balls at a big lad. At this level, his percentage dribbled past, tackles, and interceptions are in the lower percentiles. 

His passing is very strong (as it is for all Bhoys defenders due to the style the team plays). So, in Europe, being strong in the air and strong in passing is not really a difference-making profile.

Defensive action success

My standard template for assessing centre-backs uses two heavily-aggregated metrics that take all defensive actions and assesses whether they were successful (for example, did he win his duels?) and, secondly, was possession secured from the defensive action?

This methodology has a good match to the ‘eye test’ as regards assessing centre-backs.

Here the German is plotted with an array of centre-backs going back to the 2014-15 season. Carter-Vickers is in twice – for this and last season. Welsh and Starfelt have last season’s numbers used, as they do not have enough minutes completed in this one yet.

Celtic Way:

We can see that Carter-Vickers is among the best centre-backs the Scottish champions have had in this period. His numbers have taken a dip this season and this is likely to be due to the standard of opposition in the Champions League, and the aforementioned competition has accounted for 27 per cent of the team’s matches this season.

Welsh was impressive last season and it is easy to see why Postecoglou sees development in the young Scot. Starfelt does not profile well by these measures, mainly due to his poor aerial duel stats. 

Celtic Way:

However, Postecoglou clearly values other aspects of the Sweden international’s capabilities. His proactive, front-foot style of defending will lead to lots of over-committing and second-guessing, but it is likely the manager feels the benefits of his style outweigh the occasional lapses.

Being in the Jack Hendry and Efe Ambrose corner of the chart is never a good thing, but we’d hope he could at least make the ‘solid citizen’ mid-table profiles like Jozo Simunovic, Dedryck Boyata and young Welsh.

With Jenz – and allowing for an extended run with different partners and including the Champions League uplift in quality of opposition – the question is, has he done enough so far to stay permanently?

Distribution

A key aspect of the Scottish champions' centre-back play is moving the ball forward. The Hoops are possession-dominant (often enjoying 70 per cent and over) and play aggressive attacking football, looking to break the lines with forward passes.

This is measured by packing, which counts the number of opposition players bypassed by forward passes.

Celtic Way:

Here Starfelt’s data from last season has been used again and included all defenders from this season. This shows the number of opponents taken out of the game per 90 minutes per player by forward passes completed.

Welsh shows up well here but obviously has played relatively fewer minutes and not at Champions League level. 

Jenz is decent by this measure, but when we first saw him in pre-season, it looked like he could play off both feet and pass aggressively forwards. That is not something we have witnessed too often since – and certainly not consistently. He could be characterised as ‘steady’ in this area.

Packing

The packing concept covers a number of key capabilities. The ability to pass forwards, being able to receive forward passes, the ability to force opposition turnovers, putting opponents on the wrong side of the ball and the number of times a player turns over the ball taking their own players out the game.

We can aggregate all of the above to get a total packing score for each player.

Weighing all those factors up, then, here are the total pack rates for all the defenders (Starfelt has been excluded on the basis that pack turnovers and recoveries were not captured last season):

Celtic Way:

We can see that weighing up all the packing events above, Jenz has the lowest packing rate amongst the defenders. 

In particular, he is the only player in the squad with a negative pack score for defenders packed (-0.47). What that means is that he is more likely to put his own defenders out the game by turning the ball over than taking opposition defenders out the game with forward passes.

While his positional and defensive decision-making errors are generally low, he is prone to giving the ball away in dangerous areas meaning his team-mates are often out the game. Celtic tend to play an aggressive attacking game whereby the full-backs can be in quite advanced positions. It is imperative the centre-backs are safe on the ball otherwise, the risk of danger from turnovers is high.

This is an area that the man on loan from FC Lorient appears to be weak in, albeit the caveat is the fact that he is young for a defender at 23 and has been thrown into all the difficult Champions League ties.

Summary

The likely arrival of left-sided centre-back in Kobayashi suggests the Hoops are still strengthening the central defensive positions to compete with Carter-Vickers, Starfelt, Welsh and loanee Jenz.

The German has been fortunate that injuries to others have given him an extended audition for a permanent move. He has played more minutes than any other outfield player. He has had to combat the highest level of attacking teams in the Champions League.

So far, while showing glimpses of promise, especially in terms of ball progression, he has not been any more aerially dominant in the SPFL, and at Champions League level his turnover lapses have often led to dangerous counter-attack opportunities.

Can he disrupt what looks like the reconvening of the Carter-Vickers/Starfelt axis, and will the potential new signing Kobayashi supplant him in the pecking order?

There is much to play for if he is to secure that dream permanent move. At this stage, the jury must still be out on whether his deal will or should be made permanent. 


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