Bayern, who had a spectacular start to the season, dropped from top to third place in the Bundesliga last week following their 3-2 loss to Mainz 05, their second consecutive defeat in the league.
"It will be a tough game on Saturday but I expect the players to redeem themselves for last week's defeat," Bayern President Uli Hoeness (pictured) said this week. "There are no more excuses."
Hoeness said club bosses had noted a recent trend among Bayern players, who were not working as hard as earlier in the season when the team notched a six-match winning streak without conceding a goal.
"Everone is taking a step less, a little slower, a pass across more instead of going deep where it can hurt," Hoeness said.
A slip-up against visiting Bremen could let champions Borussia Dortmund, a point ahead on 29 along with surprise package Borussia Monchengladbach, pull further away.
"The team must accept the fact that they played a bad game against Mainz," Bayern CEO Karl-Heinz Rummenigge told reporters.
"If some games are not easy then you sometimes have to win the rustic way with a lot of fighting and determination."
Rummenigge rejected the argument that Bayern had been weakened by the absence of midfielder Bastian Schweinsteiger, who has been ruled out with a shoulder injury for the rest of the year.
"Obviously his absence affects the team but you can still run, fight, scratch, bite and do whatever it takes to win in the end."
Fourth-placed Bremen, missing starting keeper Tim Wiese, could also be without top striker Claudio Pizarro, who is battling to recover from a nagging knee injury in time for the game against his former club.
Bremen captain Clemens Fritz, however, has recovered from a back injury and should be fit to play.
Dortmund, who have won seven of their last eight league matches to take over top spot for the first time this season, travel to Gladbach, who in turn have won their last four games and have yet to lose at home this season.
