Following an array of injury issues, Vassell returned to first-team training last week.

But manager Steve Morison has revealed a further setback is likely to rule him out of the rest of the season, with his contract due to expire this summer.

Then Cardiff manager Neil Warnock saw off interest from Luton and Swansea to sign Vassell from Birmingham for an undisclosed fee at the start of the 2019-20 season.

Vassell scored on his debut against Luton, but since then a torn quadricep has been followed by a succession of injuries and operations that have seen him out of action for two-and-a-half years.

Aside from friendlies and under-23 matches, he has failed to feature under any of the three Cardiff managers who have followed Warnock.

Vassell's latest long-term absence sees him join captain Sean Morrison on the sidelines, the defender having suffered a serious knee injury during Cardiff's win at Barnsley.

The centre-back is another player out of contract at the end of the season, although manager Morison says he will discuss the future of the club's skipper with directors.

Despite his own position at the Bluebirds being uncertain beyond this campaign, Morison is pressing ahead with recruitment plans.

"I'd like to think that even if it's not me, the direction the football club is going means if it's not, it will be someone in a similar ilk or mould to myself who has the same ideas," Morison said.

"Hopefully it'll be a seamless transition whichever way the club decides to go, whether it's myself or someone else.

"If we go away from that, then we will be back to where we've been previously, which I am told is what we are trying to get away from."

Morison has overseen an upturn in form at Cardiff, pulling them 12 points clear of the Championship's bottom three, although he says he does not yet consider the relegation threat to be gone.

Defeat at Millwall at the weekend means Morison's team remain 20th in the table ahead of the visit of Coventry City on Tuesday.

Wales international Rubin Colwill, who missed the 2-1 loss at the Den after pulling up in the warm-up, remains out and could struggle to be fit for Saturday's home fixture with Blackpool.