Sunderland sacked manager Michael Bale after just 12 games in charge, following two consecutive defeats in the Championship.
Bale lost six games during his short spell, including a 3-0 home defeat in the FA Cup to rivals Newcastle United.
Assistant Mike Dodds was placed in caretaker charge of the Black Cats until the end of the season.
Recent defeats to Huddersfield and Birmingham have seen the Wearsiders drop to 10th in the table.
“We are disappointed that Michael is leaving Sunderland,” sporting director Christian Speakman said. The club's website said.
He added: “Our desire is to improve, and unfortunately that was not clear. As such, we bear full responsibility and feel that acting decisively is in the club's best interests.”
“These have been a difficult few months for Michael, who leaves with our best wishes for the future.”
Dodds had previously dominated Sunderland between Mowbray's exit and Bale's arrival, winning two matches – against fellow promotion rivals West Bromwich Albion and Leeds – out of three in charge.
Speakman added: “Our focus now is on the players and supporting Mike Dodds in the remaining matches to ensure we achieve the highest possible level in the league.”
“We will further update our supporters as significant developments occur.”
Bale is struggling to please Sunderland fans, who received his appointment with dismay, even though the club is only four points behind the play-off places.
Bale's exit means that his two previous jobs ended in disappointment. He was sacked by Scottish Premiership club Rangers in October after 43 games and 10 months at the helm.
His tenure was the shortest by a permanent manager in Sunderland's history, one match fewer than Paolo Di Canio's 13 appearances in 2013.
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