AC Milan's players will have to stay at their training ground indefinitely as they start a retreat following Saturday's 2-1 Serie A loss at Udinese.
Players slept at the Milanello after the game and although they were allowed home after an extra training session on Sunday, they had to be back for dinner.
The club said the 'ritiro' - confining players to headquarters - could last until the end of the season.
"The attitude today was wrong," explained coach Filippo Inzaghi.
"There are very few excuses and the only thing to do now is to roll up our sleeves and do well in the last six matches, because we're Milan and our dignity is involved.
"When you hit the bottom like today you need to reflect. It isn't a retreat of one or two days that changes things."
AC Milan, who are reportedly in takeover talks, are 10th in the Serie A table and set to miss out on European qualification.
AC Milan said: "The duration of the ritiro has not been decided.
"The team could remain at Milanello until Wednesday, or until 3 May, 10 May, 17 May, 24 May or 31 May, depending on the decision of the Milan coach, which will be based on the quality of their performances."
Milan's next game is at home to Genoa on Wednesday.