Despite Bayern's steady climb up the table to fourth place following a bad start to the season, Van Gaal knows a Bundesliga title defence is all but impossible with a 14-point gap to leaders Borussia Dortmund.
The team's season, his second in charge, is far less convincing than last year when they won the domestic league and Cup double and reached the Champions League final.
Van Gaal has also been chastised by club boss Uli Hoeness for what he said was the coach's refusal to take on board other opinions and running the team as a one-man show.
Days ago team manager Christian Nerlinger reprimanded the coach over comments regarding the length of Franck Ribery's injury break speaking as "Van Gaal's superior".
Bayern bosses also said they had wanted captain Mark van Bommel to stay after he signed for AC Milan this week blaming Van Gaal for his departure.
A 4-0 win over second-division Alemannia Aachen on Wednesday to grab a spot in the German Cup semi-finals on Wednesday helped lift some of the pressure.
"We have no injuries, Arjen Robben is fit after a flu and things look good for Bremen," Van Gaal told reporters after the Cup win.
However, he did voice some concern over his new first choice keeper Thomas Kraft who made one spectacular save but looked unsure on several occasions.
"I am not really satisfied with him. He was uncertain at some situations," Van Gaal said.
Bayern will most likely be without winger Ribery, who is nursing a minor muscle injury but Robben, who recently returned from a long injury break, looks to be back at his best.
Bremen, with only one win in their last five games and just three points off the relegation spots, are a pale shadow of Bayern's once mighty domestic rivals.
Coach Thomas Schaaf and manager Klaus Allofs are aware their long-time parternship could edge closer to an end with defeat in front of a home crowd.
Leaders Borussia Dortmund on 47 points, who had midfielder Shinji Kagawa ruled out with a broken bone in his right foot at the Asian Cup, travel to VfL Wolfsburg on Saturday.
Bayer Leverkusen, second on 36 points, could cut Dortmund's lead to eight with a win against Hanover 96 on Friday.
