Forget Scales: Celtic’s £6m defender has quietly become a major concern

Celtic made ten additions during the summer transfer window, but one area that surprisingly escaped significant attention was central defence.

Martin O’Neill and his staff opted against bringing in another established centre-back, instead choosing to work with the options already available at Parkhead.

That decision has increasingly come under scrutiny, particularly with Liam Scales continuing to divide opinion and Cameron Carter-Vickers struggling to rediscover his best form.

The lack of another experienced option could prove costly if Celtic’s defensive problems continue after the international break.

Celtic needed another centre-back this summer

Celtic’s central-defensive department has undergone constant change since Ange Postecoglou left the club.

A number of recruits have failed to establish themselves, while several temporary solutions have also come and gone.

Gustav Lagerbielke and Maik Nawrocki struggled to become regular starters, while loan arrivals including Nat Phillips, Jahmai Simpson-Pusey and Benjamin Arthur were unable to provide a long-term answer.

Celtic therefore appeared to have an opportunity this summer to bring some stability to the position.

Instead, the club chose to retain its existing options.

Dane Murray was identified by Shaun Maloney as a player capable of making a significant step forward, but the 23-year-old’s performances during important matches last season showed that he may still need more time.

Auston Trusty has also fallen down the pecking order, with Scales preferred in recent matches.

That leaves Celtic looking particularly vulnerable if injuries hit the position.

Scales is not the only problem

Scales has received plenty of criticism for his performances, and his display in the recent 1-0 defeat to Rangers did little to silence his doubters.

The Republic of Ireland international has generally been a dependable squad player during his Celtic career, particularly when injuries have ravaged the club’s defensive options.

However, his limitations in possession remain an issue.

Scales has averaged 11.2 possessions lost per Scottish Premiership game this season, while he gave the ball away 18 times during the defeat to Rangers.

Those numbers underline why Celtic may have benefited from recruiting a higher-level option on the left side of the defence.

But focusing entirely on Scales risks overlooking another issue that has developed at the heart of O’Neill’s back line.

Carter-Vickers’ form should concern Celtic

Cameron Carter-Vickers has quietly endured a difficult period since returning from a lengthy injury absence.

The American defender missed most of the 2025/26 campaign, so some rustiness was always understandable after such a long spell on the sidelines.

However, his recent displays have gone beyond simple readjustment.

Carter-Vickers once established himself as one of the standout defenders in Scottish football, with Ange Postecoglou previously describing him as the best defender in the country.

That level has not been evident consistently since his return.

The Champions League play-off against LASK exposed some of his current shortcomings.

Carter-Vickers struggled during the first half at Celtic Park and was fortunate on occasions that the offside flag came to his rescue.

His trademark recovery speed also appeared diminished, while the second leg in Linz produced further problems for the Celtic defence.

The situation became even more concerning when Celtic lost both Kieran Tierney and Carter-Vickers to injuries as the tie moved towards extra time.

Carter-Vickers was nevertheless able to feature just days later against Falkirk.

The Rangers defeat highlighted the problem

Carter-Vickers’ struggles were again apparent during Celtic’s League Cup defeat at Ibrox and subsequently in the 1-0 Premiership loss to Rangers.

The American’s comments afterwards, in which he described Celtic’s performance as “random”, also attracted attention and prompted discussion about the relationship between the players and coaching staff.

That aspect may have been overstated, but there is little doubt that Carter-Vickers needs to improve his individual performances.

Scales and Trusty are usually the defenders who attract the most scrutiny when Celtic’s back line comes under pressure.

This time, however, Carter-Vickers deserves his share of the spotlight.

He remains an experienced and talented centre-back who has shown previously that he can dominate Scottish football when fully fit and confident.

But Celtic need that version of Carter-Vickers to return after the international break.

With the club choosing not to strengthen at centre-back during the summer, O’Neill may have to rely heavily on his £6m defender rediscovering his best form.

If he cannot, Celtic’s decision to leave the position untouched could become an increasingly significant problem as the season progresses.