The Coventry City striker will miss the rest of the season with a groin strain that requires an operation.
"Leon's groin injury is quite high up and therefore hard to treat so it looks like it is going to need an operation to sort that out and we are keen to get it done as soon as possible," said Chris Coleman to the CT.
"We can't waste any time and we have just got to get it sorted out. "Belly is the same and he will hopefully get his operation this week to ensure he has recovered in time to get a full pre-season under his belt."