FRANKFURT, Germany (AP) -- Second-place Bayer Leverkusen hosts fourth-ranked Schalke, while Borussia Dortmund plays Eintracht Frankfurt as the Bundesliga weekend can produce some reshuffling behind the runaway leader Bayern Munich, which is at home against Freiburg. But the match of the day could be the showdown between the two bottom clubs, Hamburger SV and Eintracht Braunschweig.
Here are five things to know going into the 21st Bundesliga round:
With the championship all but decided, it was Hamburg's self-destruction that hogged the headlines the past week. Hamburg is the only team never to have been relegated since the Bundesliga's inception in 1963. But that proud record is in danger following six straight league defeats that dropped the club to next-to-last.
On Wednesday, Hamburg was easily swept away 5-0 at home by Bayern in the German Cup quarterfinals and the gap in class must have been frightening for Hamburg supporters.
The club's complicated leadership structure hasn't helped, with board members apparently split on coach Bert van Marwijk's future. It's far from certain that the Dutchman will be on the bench when Hamburg plays in Braunschweig, which he has described as "the match of the year" for his team.
Braunschweig is four points behind Hamburg but another defeat for Hamburg would mean an uphill battle to avoid relegation.
Hamburg has already conceded a league-high 47 goals and could be without midfielders Rafael van der Vaart and Milan Badelj .
Leverkusen is already 13 points behind Bayern and its priority now is to hold on to second place. It has lost three out of its past six, but the most recent two were victories -- until a German Cup quarterfinal 1-0 loss at home to second-division Kaiserslautern.
Schalke, on the other hand, has won four of its past five, with one draw. Leverkusen is still safe, four points ahead of Dortmund and six over Schalke, but another home defeat would tighten the race for second and third -- the Champions League slots.
Dortmund and Frankfurt meet for the second time this week. In Frankfurt, Dortmund won on a late goal by Pierre-Emerick Aubameyang to reach the German Cup semifinals, although for long stretches, Frankfurt was on even terms. It will be without captain Pirmin Schwegler because of a rib injury.
During the match in Frankfurt, defender Carlos Zambrano and Dortmund's star striker Robert Lewandowski barely avoided coming to blows, and chapter two of their showdown could be decisive for the outcome in Dortmund.
Hamburg is not the only northern German club in trouble -- Werder Bremen also has been dropping down the standings. Now 13th, Bremen has won only one of its past nine games and is three points away from the danger zone. Its 20 points from 20 matches is its worst record in 39 years.
Bremen is coming off a 5-1 loss at home to Dortmund and next meets another Borussia, fifth-ranked Moenchengladbach, also at home.
Coach Robin Dutt is under pressure to revive the team's previous trademark attacking style. While failing to create up front, Werder has also slipped in the defense, which is now the second worst after Hamburg with 45 conceded goals.
STUTTGART'S FALL: Stuttgart has lost its last four and is now one point behind Bremen as it heads to the away match at high-scoring Hoffenheim. Stuttgart will be without top striker Vedad Ibisevic -- a former Hoffenheim star -- who is at the start of a five-match ban for a red card.
First-season coach Thomas Schneider is expected to reshuffle the lineup, with Mohamed Abdellaoue taking Ibisevic's place.
Hoffenheim will strive to recover from a 3-2 home loss to Wolfsburg in the German Cup.