Bremen, in 14th place and three points above the relegation zone, is fighting for survival after conceding 39 goals in 19 games, while fourth-place Bayern scored 27 times in seven matches across all competitions since it was last beaten, in December.
Mario Gomez, the Bundesliga's joint-top scorer, found the net again as Bayern advanced to the semifinals of the German Cup with a 4-0 win at second-division Aachen on Wednesday, and will hope to add to his league tally of 15 after hitting a hattrick against Kaiserslautern last weekend.
Arjen Robben should be fit after recovering from a cold, but Franck Ribery will be out injured for longer than expected. The French winger is expected to miss another three weeks after suffering a ligament sprain in his left knee at Wolfsburg on Jan. 15.
It will be the defending champion's first league game without Mark van Bommel, the former captain signing this week for AC Milan.
Werder coach Thomas Schaaf is under pressure after his side's 3-0 capitulation at relegation-threatened Cologne last weekend. The 49-year-old Schaaf has been concentrating on defense in training this week.
"We need to keep going," Wolfgang Rolff, Schaaf's assistant, said. "Bayern has quality in attack."
On Friday, second-place Bayer Leverkusen - 11 points behind leader Borussia Dortmund - hosts third-place Hannover, which is two points further behind on 34.
Michael Ballack is tipped to start for Leverkusen after an impressive return from injury at Moenchengladbach last week, when he came on as a substitute.
"He is fitter now than after his first injury (last summer)," Leverkusen coach Jupp Heynckes said.
On Saturday, Dortmund travels to 11th-place Wolfsburg, which finally got a win after seven successive draws in the league with a late goal at Mainz last weekend.
Dortmund has been dealt a blow with the news midfielder Shinji Kagawa may miss the rest of the season after suffering a suspected broken metatarsal while playing for Japan at the Asian Cup.
The 21-year-old Kagawa had been one of the league's most impressive performers, with eight goals following his transfer from J-League club Cerezo Osaka last summer, before joining up with his country for the Asian Cup at the start of January.
Klopp will be hoping rising star Mario Goetze can continue his fine form in the Japan international's absence. The 18-year-old midfielder scored Dortmund's only goal from a host of chances in the disappointing 1-1 home draw with Stuttgart last time out.
Schalke fans will be looking to another rising star, 17-year-old Julian Draxler, to help continue the club's resurgence at home to Hoffenheim, after his stunning winner in the last minute of extra time - three minutes after he had come on - sent Schalke through to the semifinals of the German Cup at the expense of Nuremberg on Tuesday.
Schalke is 10th with 25 points and could overtake Hoffenheim, which has 26 in eighth place.
Draxler is likely to start on the bench again, as coach Felix Magath is keen to protect the fans' new hero.
"Physically, he is not yet ready, so we are not going to risk an injury," Magath said.
Also Saturday, it's: Kaiserslautern vs. Mainz; Nuremberg vs. Hamburg; and St. Pauli vs. Cologne.
On Sunday, it's: Stuttgart vs. Freiburg; and Eintracht Frankfurt vs. Borussia Moenchengladbach.
