Last season's double winners were dumped out of the German Cup with a home defeat by Schalke 04 on Wednesday and are down in fourth place in the Bundesliga, 16 points behind leaders Borussia Dortmund.
While they are still alive in the Champions League, their only domestic target is now second place and automatic qualification for next season's competition, making Saturday's trip to face third-placed Hanover 96 a vital game.
"It is extremely important that we remain calm despite the bitter disappointment and the emotions we may be feeling at the moment," Rummenigge said on the club website on Thursday.
Bayern are on 42 points, four points off second-placed Bayer Leverkusen after losing to Dortmund 3-1 last week, another home defeat.
"We just have to swallow these results and move on. We have no choice. What is important is that we beat Hanover first and take it from there," Rummenigge said.
Bayern coach Louis van Gaal, who has had his share of run-ins with club bosses this season, knows any slip-up against Hanover could prove costly for his team as well as his own job prospects.
At least Van Gaal will have a full squad to pick from for the game at Hanover, one of only a handful of occasions this season he has had that luxury.
Hanover, though, will be no pushover as the perennial relegation candidates lie two points ahead of Bayern.
Top Hanover striker Didier Ya Konan is still out with a knee injury but his team finally managed to win without him last week against St Pauli after failing to do so in 10 previous games he had missed in the last 18 months through injury or suspension.
"We want to bring him into the team gradually. We do not want to rush it," Hanover coach Mirko Slomka told reporters.
Dortmund will be looking to become the first visiting team in six games to snatch at least a point in Cologne on Friday with the hosts having won their last five home games.
Leverkusen host lowly VfL Wolfsburg, who are struggling in 14th place two points off the relegation play-off spot.
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