Brentford boss Thomas Frank is unsure when Mathias Jensen will again be fit.
The midfielder has been battling with injury.
"I try to be honest and tell it like it is," said Frank.
"Some injuries are a bit trickier. It is related to his tendon in the muscle.
"That's why it doesn't heal like we thought it would. He is out on Sunday (against Aston Villa).
"He may be ready for Wolverhampton (December 27), but it may also be that he is not ready before the Nottingham Forest game (January 20)."