Injury delays Rajkovic's Hamburg comeback
The 23-year-old, who was sent to the reserves in July after fighting with a team mate during training and calling his coach Thorsten Fink "two-faced", had been due to rejoin the senior team on Wednesday.
"He will be out for two or three weeks," Fink said on the club website. "I feel sorry for Boban. He had big plans but now he has been ruled out."
The coach had said recently he would give the strong defender a second chance.