Louis van Gaal has divided Bayern Munich into two, in a bid to keep 11 players fit for the matches against Dortmund and Fiorentina.

As the Dutchman reported after his side's 6-2 victory over Greuther Furth in the DFB-Pokal on Wednesday, a virus is currently doing the rounds.

"That is bad because we have some important midweek matches coming up and we expect even more players to fall ill in the coming weeks," he said.

Therefore, Van Gaal invited half of his squad to training yesterday morning and the other half yesterday afternoon in a bid to keep those known to be infected away from those who, so far, have not shown any symptoms.

"The rest will train at a different time," reported defender Philipp Lahm on the club's website.

"We can only hope that we don't catch anything."

Lahm is one of the fit players who did the rounds in the snow yesterday morning and his place in the team against Dortmund tomorrow should be guaranteed.

Ivica Olic, Bastian Schweinsteiger, Daniel van Buyten, Danijel Pranjic, Hans-Jorg Butt and Miroslav Klose all remain doubts, on the other hand.

Dortmund coach Jurgen Klopp has no such worries after welcoming three key players back into training this week.

Jakub Blaszczykowski, Sven Bender and Roman Weidenfeller are all available again, leaving Klopp optimistic.

"We are not just going there to have a look at the stadium," he said. "If we give it 100%, then we can steal the fun of playing football from our opponents."