There are few cases more curious in Scottish football than that of Olivier Ntcham.
When at his best for Celtic the French midfielder had a genuine claim to being the pre-eminent midfielder in Scotland, able to control a game almost on his own.
One of the high water marks of the Brendan Rodgers era was a 5-0 demolition of Rangers at Parkhead in April 2018 and Ntcham was the chief tormentor of the Ibrox side.
At just 22 he combined physical gifts with extraordinary technique to leave players either twisted in knots or simply bouncing off him - a YouTube compilation of his every touch from that match runs to a full six minutes.
The former French youth international clearly had talent, having been signed by Manchester City and played in Serie A, and it looked like he was ready to achieve his full potential in Scotland.
His first season convinced Porto to offer more than £13million for his services, with that offer booted out by Celtic.
At the age of 26 though, where the likes of Kieran Tierney, Odsonne Edouard and Kris Ajer are shining in Europe's top leagues, a player who should be in his prime is turning out for Swansea in England's Championship.
With all due respect to the Swans, it's not where Ntcham probably saw his career going - so what's happened to the man who was so dominant on that April day?
Celtic fans don't need much of a refresh on his time at Parkhead. Interest from abroad turned his head, and despite some huge highs - that winner away at Lazio will go down in history - was accused of having downed tools.
Ntcham was eventually shipped out on a dream loan move to Marseille, only to see boss Andre Villas Boas resign in protest at his signing.
Successor Jorge Sampaoli didn't have much time for the former Genoa man either, regularly subbing him at half-time - as the interim boss did in a shambolic Coupe de France defeat to fourth-tier Canet Roussillon.
OM didn't take up their option to buy, and Celtic didn't even ask Ntcham to see out his contract, with the two parties agreeing a termination despite his deal having 12 months to run.
That happened on August 1 2021, but a player who was once coveted by Porto and others didn't find another club for a month.
The Frenchman eventually turned up at Swansea, where his story will be familiar to Celtic fans - the quality is there but the consistency is not.
Ntcham has completed 90 minutes just twice in the Championship this season, but has weighed in with three goals and two assists.
With a pass completion over 84.5 per cent the 26-year-old can still be a Rolls Royce, but he came in for some heavy criticism following the 4-0 defeat to Sheffield United at the weekend.
However, the idea that Swansea supporters are hostile to their summer signing is wide of the mark.
One diehard Swans fan told Record Sport: "When he plays he’s been really good, for the most part.
"The problem is, he didn’t have a pre-season before he came in, so we’ve not seen a lot of him. He scored a screamer against Luton early on in the season, which was the first meaningful action after him playing like 10-20 mins per game. It’s kind of carried on like that.
"He’ll play one game, look alright, then barely cover 90 minutes. You may see people saying he was played as a second striker on Saturday and is generally unpopular with Swans fans - neither is true.
"He plays as a 10 (which obviously has limited success, because he never looks bothered), but I think that was more scapegoating on Saturday than him being consistently unpopular if you get me."
Ring any bells, Celtic fans?
With Russell Martin's side sitting 17th, well clear of the relegation zone but hugely inconsistent, Ntcham's languid style makes him an obvious target when things go badly - just as we saw in his time at Parkhead.
Last season's 4-0 humbling at home to Sparta Prague saw the midfielder targeted for his perceived lack of effort, and it's an accusation that has dogged him throughout his career.
The fact he made just two Ligue 1 starts under Sampaoli, famous for his high-intensity pressing game, is likely linked to the impression, deserved or not, that Ntcham just isn't willing to do the dirty work.
At 26 he should be entering his prime, and there's still time for the former Celtic man to find a settled spot and play as we know he can.
With Swansea lying 17th in the Championship though, Ntcham looks a long way from the player who ragdolled Rangers four years ago.
