LEVERKUSEN, Germany -- Bayer Leverkusen are fretting about the fitness of three key players ahead of their Champions League match against Bayern Munich on Tuesday.

Florian Wirtz, Granit Xhaka and Edmond Tapsoba were all taken off early in Leverkusen's 2-0 loss to Werder Bremen in the Bundesliga on Saturday.

The club fears the worst for Wirtz, who suffered a right foot injury after going on as a half-time substitute.

Leverkusen coach Xabi Alonso said Wirtz was on his way to hospital before the match ended.

Alonso said he took off Xhaka and Tapsoba at half-time because they were having difficulties.

"We don't know yet if they're injured or they just have knocks," Alonso said. "Granit and Edi had a few problems, that's why we took them off. We have to wait and see."

Leverkusen need to overturn a three-goal deficit against Bayern on Tuesday after losing the first leg of their last 16 tie in Munich on Wednesday.