United are waiting to discover the extent of the Mexican striker’s injury.
United managed to beat Chelsea 3-1 at Old Trafford on Sunday.
Ferguson felt that his side should have been given a spot-kick following Cole’s challenge on Hernandez.
“I don’t know what we’re going to do,” Ferguson told Sky Sports.
“To me it was a shocking tackle, an absolutely shocking tackle.
“The referee has booked him, but if he’s booked him, I don’t know why it wasn’t a penalty. I must ask him.
“We’re going to have to wait until the morning. At the moment his leg is very numb and he doesn’t have any feeling, so he could be out for a couple of weeks maybe.”
