Köln - 1. FC Köln striker Patrick Helmes faces an indefinite spell on the sidelines after being diagnosed with cartilage damage to the hip.
"The medical team and physios will take care of Patrick," Köln's team doctor Dr. Peter Schäferhoff explained. "We'll decide when he's ready to return depending on how the treatment goes."
Helmes, who only recently returned to team training following a thigh problem, scored 12 goals and chipped in with six assists in 27 league appearances last season as the Billy Goats secured promotion to the top flight as Bundesliga 2 champions.
The 30-year-old's latest injury setback represents a bitter blow for Peter Stöger's men, who already look set to be without Dusan Svento (foot) and Kazuki Nagasawa (knee) for their opening fixture of the 2014/15 campaign at home to Hamburger SV on 23 August.