Cumbrian goalkeeper Dean Henderson has suffered a setback in his return from injury.
Nottingham Forest boss Steve Cooper said the Premier League star, from Whitehaven, is "frustrated" at being no closer to a comeback.
Cooper described the setback as "small" but could not be certain if the Manchester United loanee would play again this season.
Henderson has been sidelined since January with a thigh injury.
Speaking to NottinghamshireLive, manager Cooper gave an update on the 26-year-old's situation.
"He's not back in training. He's not really any closer,” Cooper said.
"He's still in the medical room, unfortunately, so we'll see where that takes us in the next week or so.
"I hope he will play again this season, but I don't know, to be honest. It's a bit inconclusive on that, so we'll see.
"It's just been ongoing. There has been a small setback.
"The other thing with Dean is he's a Man United player and you have to work in conjunction with them.
"He's had a small setback, in terms of his recovery, but he is working hard. He's frustrated, as you can imagine.”
Henderson's injury came after 20 appearances for Forest as he returned to Premier League first-team football.
His early-season form led to an England recall, while the Cumbrian has been linked with a permanent move away from Manchester United, with Tottenham Hotspur and Aston Villa among the clubs said to be interested.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here