Germany winger Sidney Sam has been ruled out of Bayer Leverkusen's Champions League clash at home to Manchester United on Wednesday after tearing a thigh muscle.

The 25-year-old limped off after just four minutes of Leverkusen's 1-0 Bundesliga win at Hertha Berlin on Saturday and a scan on Sunday revealed the extent of the injury.

"The loss of Sidney is very bad news," Bayer's director of sport Rudi Voeller said on the club's website.

"This is the game of games for us in the Champions League, we have to put all our power and effort into it, just without Sidney."

Leverkusen have not said how long Sam is expected to be out for, but with less than a month left before the winter break, the Germany winger faces a race against time to be fit again in 2013.

Leverkusen are second in Group A, just one point behind David Moyes's Premier League side.