Duisburg have suspended Brazilian striker Ailton and told him to look for a new club after he returned late to training.
The 34-year-old took an extended his stay in Brazil without consulting the club and then complained of a flu-like virus.
Coach Rudi Bomme has told the forward he no longer features in his future plans and can leave the MSV-Arena after he failed to to turn up for training on Thursday.
Club chairman Walter Hellmich confirmed that the former Bundesliga top-scorer, who joined in the summer from Red Star Belgrade, will not be involved with the first-team squad.
"He will train on his own, we cannot do anything else," Hellmich told www.kicker.de.
"We are definitely planning our future without him, and he will not train with the team."