Mats Hummels last night branded Borussia Dortmund “pathetic” as he raised major doubts about his future there.
The defender is a January target for Manchester United and his remarkable attack may have opened the door to him leaving.
The 26-year-old would cost United more than £45million, but he is also on the radar of Europe’s other top clubs.
German giants Dortmund finish 2014 second bottom of the Bundesliga after a 2-1 defeat at Werder Bremen in their last game before the winter break.
And it has raised major doubts over the futures of Hummels and manager Jurgen Klopp.
World Cup winner Hummels said: “We’ve managed pretty well at home in recent weeks, but not at all away.
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“It’s pretty astonishing that we are so pathetic.”
Klopp has led Dortmund into the Champions League last 16 but admits he cannot explain their disastrous form, especially away from home. They have managed just 15 points from 17 league games.
Klopp said: “It was just a reflection of our whole season so far.
“We had a very poor first half. It follows suit that we are standing here like total idiots.”
But Klopp, linked with Liverpool and Arsenal, has ruled out quitting.
He added: “I am totally responsible and I am not just going to throw in the towel. We are going to put right what we’ve done wrong.”