Well it's clearly not a playing injury as he was on the bench yesterday. Whatever it is, fingers crossed for the lad.
Injuries don't only happen in matches.
The worst football type of injury would be a leg break which fucks up the knee - Posterior Crucial Ligament (PCL), Medial Collateral Ligament (MCL) and Anterior Cruciate Ligament (ACL). That would be a year out.