Celtic midfielder Scott Brown faces a race against time to be fit for Thursday's Europa League clash with Atletico Madrid.
The 26-year-old missed the Bhoys' 4-0 Scottish Premier League win over Motherwell on Saturday due to an ankle injury.
The Scottish international injured the ankle during training on Thursday and Celtic manager Neil Lennon fears the club captain could miss the trip to Madrid in mid-week.
"It's one where he needs rest but with the fixtures it is difficult to give him that rest," said Lennon.
"He is such a good player and a valuable player for us, I don't like leaving him out at anytime."
Brown joined Celtic from Hibernian in 2007 and has gone on to score eleven goals in 122 appearances for the Parkhead side.
