Bayern Munich stars Arjen Robben, Robert Lewandowski and Thiago Alcantara all suffered injuries during Tuesday's DFB-Pokal loss to Borussia Dortmund, putting in doubt their status for next week's Champions League semifinal against Barcelona.

Robben had to be substituted just 16 minutes into his return from a month out with an abdominal injury.

Thiago left the pitch earlier in the match after suffering a knock, prompting Pep Guardiola to replace him with Robben, but the move backfired when the Dutchman sat on the turf and grabbed his calf muscle.

"He's injured," Guardiola said of Robben, and the club said the winger will undergo a full diagnosis on Wednesday.

Bayern also confirmed after the game that Lewandowski was hospitalised after suffering a concussion.

Lewandowski was injured in the 116th minute on a collision with Dortmund keeper Mitch Langerak. The striker stayed in the game but was notably absent from the shootout as the hosts missed all four of their penalties.

Bayern wrapped up the Bundesliga title last weekend, but the injuries come eight days before their crucial first-leg clash against Barcelona at the Camp Nou.

The German champions are already preparing to play without Franck Ribery, who has been out with an ankle injury since March, and David Alaba, who is dealing with a knee injury.