With only one point from its last two matches, Borussia Dortmund has seen its once massive Bundesliga lead cut to seven points.
Dortmund will be looking nervously over its shoulder at approaching Bayer Leverkusen when it hosts Hannover, which is enjoying its best season and has lost only one of its last seven games in Dortmund.
Hannover is looking to hold on to third place, which secures a slot in qualifying for the Champions League, ahead of defending champion Bayern Munich.
Leverkusen travels to relegation-threatened Kaiserslautern, also Saturday.
Dortmund defender Neven Subotic, cleared to play after picking up a foot injury on international duty for Serbia, is not worried about his team losing pace.
"Even when we haven't played that well this year, we were at least even or slightly better than the opponent," Subotic said. "We were unfortunate in some recent games."
Hannover lost at home to Dortmund 4-0 but the team that narrowly escaped relegation last season could make the season ending interesting again if it manages to upset the leaders. There are seven games left.
"That would be nice for the fans but we really want the points for ourselves," Hannover defender Christian Schulz said. "It's a top game and we've worked for it."
Hannover is two points ahead of Bayern Munich, which is also trying to reach a Champions League slot and hosts last-place Borussia Moenchengladbach.
"This match is a great challenge," Hannover coach Mirko Slomka said. "We want to defend our position."
Hannover has been one of the success stories this season and Slomka said a change in attitude is responsible for the turnaround.
"Last season we only reacted and looked out for what the opponents were doing. Now we have our own strategy and we are capable of implementing it," Slomka said. "We don't allow many chances and we are good in the air."
Schulz said the team has become much more stable.
"We are difficult to beat," he said.
Leverkusen plays its first match since coach Jupp Heynckes announced that he would be leaving at the end of the season to take over at Bayern.
Heynckes is in a strange situation - trying to deny his future club of a place in the Champions League.
Leverkusen can mathematically still win the title, but it's second place that is their goal at the moment.
"We have to keep Hannover and Bayern behind us," Leverkusen striker Stefan Kiessling said. "That's our job. What happens with Dortmund is outside our control."
Two coaches will be making their debuts at new clubs at this late stage of the season - Ralf Rangnick in his return to Schalke and Christoph Daum at Eintracht Frankfurt.
Schalke kicks off the round Friday at St. Pauli. Eintracht visits Wolfsburg on Sunday, with both clubs battling against relegation. Wolfsburg, the 2009 champion, recently hired Felix Magath after his firing from Schalke.
Also Saturday, Werder Bremen hosts Stuttgart, Mainz plays Freiburg and Hoffenheim meets Hamburger SV, while Nuremberg visits Cologne on Sunday.
