Very, very nervous. He couldn't even walk and he's not one to stay down or exaggerate injuries.
His ankle is about to be very swollen for a few days I reckon. Not a bad injury if you don't have previous (like Wilshere).
Your ankle hurts like a fucking cunt, and it's a bloody nightmare getting around, even getting to sleep.
But he won't be away too long, they'll have him straight to the locker room for some RICE treatment and he'll be gone for maybe two weeks at most.
However, I'm no doctor, so this is just speculation.