Felix Magath led Bayern Munich to back-to-back league and cup doubles but life has not quite been the same in Bavaria since.

He was sacked in early 2007 with the club third in the Bundesliga and still going strong in the Champions League.

His successor Ottmar Hitzfeld was unable to prevent them from sliding to fourth in the table at the end of that season, although after leading them to a double in 2008 nobody has been able to latch onto their success.

Bayern have changed coaches three times already in 2009 with Jurgen Klinsmann replaced by Jupp Heynckes, who in turn passed on the baton to the current coach Louis van Gaal.

Magath could be the man to force Bayern to make their fourth managerial change of the year if his Schalke side can come up trumps at the Allianz Arena on Saturday.

However, Van Gaal is not concerned about such rumours.

"That is not an issue for me," he said.

"I never think about such things.

"I cannot make such decisions. I can only support my players and protect them."

Schalke could move to the top of the table with a win while Bayern could move to their highest position of the season, jumping above their opponents, with all three points.

Bayer Leverkusen have the chance to race away at the top when they host Eintracht Frankfurt in the weekend's opening fixture tomorrow night.

They currently hold a one-point advantage over Werder Bremen, who are not in action until Sunday due to their Europa League commitments.

That also causes third-placed Hamburg to have to wait until Sunday before travelling to Hannover, which is why Schalke, Bayern and Hoffenheim, who host Wolfsburg, will all be looking to take full advantage on Saturday.

Elsewhere, Borussia Monchengladbach host Stuttgart in a relegation battle with Bochum also needing points against fellow strugglers Freiburg at the Ruhr Stadion.

Sunday's other game is also a relegation battle between Hertha Berlin and Cologne.