Bayer Leverkusen winger Leon Bailey was ruled out for at least four weeks Thursday with an injury sustained in their shock Champions League loss at home to Lokomotiv Moscow.

The 22-year-old Jamaica international tore a leg muscle in Wednesday's 2-1 defeat and will miss their next Champions League match at Juventus on October 1.

Bailey was at fault for Lokomotiv's first goal while another error by Leverkusen goalkeeper Lukas Hradecky led to the Russian side's second.

The setback in Europe came on the back of Saturday's 4-0 hammering at Borussia Dortmund in the Bundesliga, prompting a stinging rebuke from Leverkusen director Rudi Voeller.

"That was sub-standard before the break and not the level of the Champions League, we haven't seen a performance like that from our team for a long time," said former Germany coach Voeller.

"This defeat hurts me more than the 4-0 in Dortmund, where the result was too high in the end, but we were still better than against Moscow.

"Of course, there were those two mistakes but we can't reduce that to these two errors, that would be too easy - in the first half we were all a bit too scared."