Chelsea duo Mateo Kovacic and Andreas Christensen face a race against time to be fit for Saturday's FA Cup final.
Croatia midfielder Kovacic has been sidelined with hamstring trouble since the day before the Blues' Champions League quarter-final second leg with Porto on April 13.
Denmark defender Christensen picked up a tendon problem in Saturday's 2-1 Premier League win at Manchester City and will also be a doubt for the weekend's Wembley showdown with Leicester.
Kovacic and Christensen will both miss Wednesday's Premier League clash with Arsenal at Stamford Bridge.
Blues boss Thomas Tuchel suggested however that Kovacic could stand more chance of being fit in time to take on the Foxes at Wembley.
"Kova is not ready for tomorrow, we have to postpone it to Wembley," said Tuchel. "So his personal race is on to make it to the squad to Wembley.
"For Andreas, it's better than we feared, much better, the images yesterday, so we hope also for one of the two Leicester games for him to come back.
"It will be also a tough one, but the season is not finished for him hopefully. So we have realistic hopes that his latest comeback will be against Aston Villa."
Former Real Madrid player Kovacic missed both legs of Chelsea's Champions League semi-final victory over his old club.
The 27-year-old has excelled under Tuchel, in a deep-lying midfield role alongside either N'Golo Kante or Jorginho.
Tuchel conceded Kovacic's absence has dented Chelsea's ranks, with the German hoping the highly-regarded midfielder will win his fitness battle for Saturday.
"Billy Gilmour has had to step up now because we missed Kova so much, and we play normally always with the double-six," said Tuchel.
"So we were constantly rotating between N'Golo, Jorgi and Kova. Once we missed Kova now for so many games and so many weeks, it was on Billy to step up and I was very happy that he could deliver when it was needed. So full credit for that.
"But Kova is a big, big loss with his ability to drive with balls, with his speed on the ball, without the ball.
"Kova is such a positive character, such a unique player, and a genuine fighter on whom you can always rely in training and in games.
"He has big experience even though he's still young. So we really miss him and he's a good match with Jorgi and N'Golo in all combinations.
"So it's a big, big miss and I can't wait until he's back in full team training, and he's taking now some steps in the right direction. And I hope he can join team training after our game against Arsenal."
Christensen has hit a rich vein of form in the last few months under the stewardship of Tuchel, who is lamenting the centre-back's absence.
"Andreas was crucial in the matches where he played and now we miss him, and for some matches around the Porto game as well," said Tuchel.
"Now he has a tendon problem, and so he was crucial in the back three, he gave us a lot of options because he can play all three positions and he's very calm.
"But don't misjudge him by being calm, he is a very tough one to play against, he uses his body very well, he's very strong in individual duels and is good on the ball.
"So I think that the role in the back three suits him very, very well and I've been very impressed by his performances.
"Now we were a bit relieved yesterday when the images were given and were not as we expected in the worst case.
"So we have realistic hopes the season is not finished for him as well, and this is very, very important."
