Sir Alex Ferguson is hoping Rio Ferdinand will be fit for Manchester United's UEFA Champions League clash with Inter Milan.
Ferdinand hurt his ankle during the first half of United's FA Cup victory at Fulham on Saturday and was replaced by Jonny Evans at half-time.
The centre-half left Craven Cottage wearing a protective boot and United boss Ferguson is fretting over his stand-in captain's fitness.
If Ferdinand fails to shake off the knock, then Evans will partner Nemanja Vidic in defence for the second leg of the last 16 tie at Old Trafford.
"Rio's a bit of a concern," Ferguson told MUTV. "He's gone over on his ankle and we just have to wait and see how he is now.
"I just hope he makes Wednesday because he's such an important player to us."
Wayne Rooney was another player to be replaced during the 4-0 thrashing of Fulham, with Ferguson not wanting to take any risks with his fitness following the striker's recent return from injury.
He added: "We need Wayne for Wednesday against Inter Milan."
John O'Shea was taken off in the second half of the quarter-final FA Cup tie as well and the versatile defender appeared to be nursing a hamstring problem.
If O'Shea is unable to overcome the injury, then Darren Fletcher may be pressed into action at right-back against Inter, with Gary Neville, Wes
Brown and Rafael da Silva all injured.