Gelsenkirchen: Schalke fired coach Felix Magath on Wednesday, saying in a statement it had "very good reasons" for the move.
The Bundesliga club's board said Magath would leave the side immediately, but refused to divulge further details, citing possible legal action.
"From the point of view of Schalke, there are very good reasons for this separation," it said on its website.
Last week, Schalke said that Magath, 57, would leave at the end of the season, cutting short his contract that was set to expire in 2013.
Magath's attorney Ralf Hoecker said the coach had learned of the Schalke board's decision through the media and not yet been personally informed.
No replacement was immediately named, but the nation's mass-circulation Bild daily reported Wednesday that Ralf Rangnick is expected to take the job by the start of the next season, at the latest.
Seppo Eichkorn, previously Magath's assistant coach, took over training on Wednesday. Schalke is to play Bayern Leverkusen on Sunday.
Schalke has been plagued by inconsistency all season, sitting 10th in the Bundesliga.
But the Gelsenkirchen team is in the German Cup final after winning 1-0 at Bayern Munich and faces second-division club Duisburg.
Magath came to Schalke after leading Wolfsburg to the 2009 Bundesliga title. His task was to capture the title with Schalke, which hasn't won it in five decades.
In his first season, Magath took Schalke to second place and a direct slot into the Champions League. His second season got off to a difficult start, though, after signing 14 players and releasing several veterans.
One new signing has been a success, former Real Madrid striker Raul Gonzalez. But many other moves by Magath have raised questions and his bloated squad has failed to find the right chemistry.
Magath is the eight Bundesliga coach to be relieved of his job this season. Bayern announced last week that Louis van Gaal will go at the end of the season, and Armin Veh said he would leave Hamburger SV.