Anyone know the extent of Moss's injury?

Apparently he left practice due to a hamstring injury. He is listed as probable for the weekend though. Let's hope he plays or there will be no passing game at all.

there is really no chance for him to rest his leg.its now or never for the redskins

i heard on sportstalk 980, it was a tweeking of the hamstring, nothing more.moss said him leaving practice was precautionary