THE FULL-BACK positions at Celtic have been categorised as a “problem” area since Mikael Lustig and Kieran Tierney formed a well-balanced pairing. If you are a 'Da' like me, you might even argue it goes back to Danny McGrain's departure.

The recent years have seen a cavalcade of loanees and seemingly poor investments. Currently, Celtic have ended up with a player that looked to have no future (Anthony Ralston) and one playing out of position (Josip Juranovic). There is also the injured Greg Taylor, considered domestically strong but with accompanying doubts when the opposition level rises.

Beyond that, it’s the kids.

Like much of what Ange Postecoglou has touched so far though, there is an element of water transposing to wine. Maybe not a fine Domaine de la Romanee, but certainly a decent £15 bottle off the top shelf at Tesco. Namely, Ralston has astounded the vast majority of the support with his recent renaissance.

How good has he been, and to what extent has this most recent full-back partnership, with their inversion stylings, been responsible for a newly-robust Celtic?

Defensive performance

When assessing central defenders, two aggregated metrics will be plotted. These are:

1. Defensive Actions Success Rate (DASR%) – the percentage of defensive actions (e.g. duels, aerial duels, interceptions, shield outs) that have been successful

2. Possession Won % (PW%) – the percentage of defensive actions undertaken where possession has been won for Celtic – this does not include passes

These metrics result in a distribution that matches well with the 'eye test'. That is, top right ('good') contains players such as Virgil van Dijk, Christopher Jullien, Kristoffer Ajer and Filip Benkovic while bottom left ('bad') is the likes of Efe Ambrose and Jack Hendry.

But it is tricky for full-backs. Think Tierney – many of his duels were in the attacking third and he lost tackles attempting progressive actions. It says little about his defending, per se.

Accepting that, while understanding that all Celtic full-backs are expected to contribute significantly to attack, we shall proceed.

Celtic Way:

If you were told “Lustig is an example of a good defensive full-back” most would accept that. Therefore, it is no surprise he is top right by these metrics.

Bottom left is Jeremie Frimpong, who would be nobody's idea of a good defensive full-back. Well, apart from Bayer Leverkusen obviously.

This year’s cadre are highlighted in red. Ralston’s DASR is, at over 60 per cent, on the high side. His problem is he loses possession to a relatively high degree. Taylor would be at the bottom range of defensive full-backs. Juranovic, perhaps surprisingly, is in the middle of the pack but it is early days and he has not played his preferred position as yet.

So far so, errr, average.

Chance creation

Teams use full-backs as creative outlets to varying degrees. For the likes of Liverpool and Rangers under Steven Gerrard, they were paramount. For Celtic, it is certainly key given the propensity to play against deep blocks and defensive alignments domestically.

Next we plot chances created per 90 minutes (a pass leading to a shot) and expected assists (xA per 90min) to gauge the quality of chances provided.

Celtic Way:

It will likely surprise some just how creative Taylor is. Last season, in particular, his xA of 0.34 was eye-catching.

This can be tempered by pointing out all of this output came at SPFL level or during European qualification against perceived weaker teams (he registered zero xA in the group stages and against Rangers). Still, Ralston and Taylor look good by this view.

READ MORE: Celtic's intriguing and surprising battle of the right-backs

What is again surprising is Juranovic showing as even less creative than Diego Laxalt. Who knew that was even possible? Stay strong though, as there is always more data to compare.

Creative ball progression

Now we turn to pack passes (a forward pass that takes at least one opponent out of the game – think line-breaking passes) as well as successful crosses.

(As an aside, what constitutes a “cross” is an inconsistently defined data point across data providers. Therefore, different providers will give different numbers on this. With my data, it might be “wrong” but at least it is consistently so!)

Celtic Way:

The wee Moritz Bauer outlier is of academic interest – not a bad crosser that boy (if you remember him, that is!).

Emilio Izaguirre in 2018-19 was much age-declined. In his pomp, the Honduran would have fared well by these numbers.

But to the here and now - Celtic's current lot love line-breaking passes. The fact all are in the bottom right suggests there may be something systemic going on here as regards how players are instructed to play. Here, new signing Juranovic so far shines as the top full-back of recent seasons in line breaking ball progression. His cross success per 90min is also good.

Ralston is very good on this by peer group, but passing is the weakest part of his game (83 per cent pass completion is the lowest of any Celtic defender).

It suggests that if line breaking ball progression is a priority for the manager (and who doesn’t love playing like that?) then Taylor and Juranovic may be the best bets.

Non-passing ball progression

Finally, let’s consider getting the ball forward through carries (packing dribbles and progressive runs) and being on the receiving end of pack passes.

These indicate levels of dribbling skills, pace, movement off the ball, positioning, touch and control.

Celtic Way:

What is obvious is that ball carrying is the Frimpong superpower. None of the current crop are exceptional ball carriers (apropos nothing at all, Jota comes into Frimpong’s orbit by this measure but, whisper it, has other superpowers too).

What you can see is the little crop of Taylor’s top left. While not blessed with blistering pace, Taylor is excellent at finding space to receive forward passes and get the team up the part. The best of recent seasons in fact.

Again, Juranovic is surprisingly average by these measures given his apparent pace.


OK, that was a lot of busy charts. What are the takeaways?

Style will have an impact on how player’s metrics turn out and that manifests most clearly in the pack passing data.

That being said, Ralston is a very solid defensive full-back who is holding his own creatively within perhaps insurmountable limits – for instance, pace, general technique and vision.

Taylor is creative in the broadest sense. His challenge is to translate that performance level against better opponents.

Juranovic is somewhat being kept on the leash through not playing his preferred position. The eye test says Celtic have a very quick, well organised, balanced and dynamic player but the data doesn’t back that up completely yet.

Essentially, the conclusion here is that Celtic still need to better equip the full-back areas but that the current incumbents deserve credit for raising their game so far.