Oliver Kahn is to undergo surgery on his elbow injury and is facing up to five weeks on the sidelines.
The veteran Bayern Munich goalkeeper aggravated an existing problem during the warm-up for Saturday's Bundesliga clash against Bayer Leverkusen.
Kahn was replaced by Michael Rensing for the BayArena meeting and he kept a clean sheet as the visitors won 1-0 to open up a four-point lead over Schalke at the top of the table.
Coach Ottmar Hitzfeld confirmed that the former Germany No.1 requires an operation, but as yet a date is still to be set for the procedure.
Bayern could also be without Miroslav Klose for Thursday's Uefa Cup first round second leg with Portuguese outfit Belenenses due to a knee complaint.