Rooney required stitches to a head injury sustained during a training session on Saturday afternoon.
The striker, who has just returned to the side following a failed transfer bid from Chelsea, sustained the injury during an accidental collision with a team-mate.
The 27-year-old left the Carrington base with his head in bandages and is now also a doubt for England's World Cup qualifier double-header.
Roy Hodgson's side face Moldova at Wembley on September 6 before travelling to Kiev to play Ukraine four days later.
It was later confirmed that Rooney was not on the team bus as it departed for Anfield.