Manchester United manager Sir Alex Ferguson has revealed that Tom Cleverley's calf injury is "not good news".
The midfielder was forced off before half time in Wednesday's 1-0 defeat to CFR Cluj in the Champions League.
"Tom felt his calf a little bit," Ferguson told Sky Sports News. "We will assess it in the morning but it is not good news."
Cleverley is expected to be a major doubt for United's visit to Manchester City in the Premier League on Sunday.