With the World Cup just around the corner, there are clearly going to be fears that Rooney could be out of the tournament.
There is no news on the severity of the injury but it may have something to do with the fact that Ryan Giggs introduced double training sessions for the team today.
The reality is that any sort of injury is bad news for Rooney because more than most players, he needs regular football to maintain his match fitness otherwise he loses his sharpness very quickly.
Giggs will more than likely reveal some more information about Rooney in his Sunderland pre-match press conference tomorrow morning.
Update – Contrasting reports now suggest Rooney missed training altogether through a stomach bug.
People close to Wayne Rooney tell us he missed training because of a stomach complaint rather than any injury – panic over?
— Dan Roan (@danroan) May 1, 2014