FC Bayern München face selection problems ahead of their UEFA Champions League semi-final decider at Olympique Lyonnais after Anatoliy Tymoshchuk was ruled out, with doubts persisting over centre-backs Martín Demichelis and Daniel Van Buyten.

Ukraine midfielder Tymoshchuk, 31, has not travelled to France for Tuesday's second leg after suffering a bout of gastroenteritis. Both Demichelis and Van Buyten have minor calf problems, but do make the trip as Bayern bid to defend a 1-0 lead and progress to a first UEFA Champions League final since their 2001 success.

Van Buyten picked up his injury in Saturday's 1-1 Bundesliga draw at VfL Borussia Mönchengladbach and said: "I received a knock to my calf and fear I won't make it for Lyon." However, Bayern coach Louis van Gaal was more optimistic. "I hope that at least one central-defender will be fit," the Dutchman said. "Then we have [Holger] Badstuber, the other central-defender and [Diego] Contento for left-back. Then it will be fine."

Van Gaal's worries do not end there, however. Miroslav Klose, scorer of Bayern's equaliser at Mönchengladbach, has also emerged as a doubt. The Germany striker missed Monday's training session at Stade de Gerland with a cold.

There was some good news from the Bayern camp, though, as Hamit Altıntop trained with the team on Sunday after recovering from a groin problem. The Turkish international will be available to play.