Coppell told the Reading Evening Post: "Leroy's in a great deal of pain.
"He woke up and stretched while in bed and he's done something to his leg. It isn't an injury that should be ridiculed or made light of.
"We don't know what happened exactly. It looks to be a problem with a nerve. Maybe he's displaced one, but he could hardly walk on Monday and had to sit out training.
"It came on so dramatically that we're just hoping it goes away as quickly."