Hoffenheim striker Vedad Ibisevic will miss the rest of the season after tests confirmed he has torn knee ligaments.
The Bundesliga's leading goalscorer sustained the injury on Wednesday and now faces six months on the sidelines.
The 24-year-old Bosnian had scored 18 goals in the first 17 matches of the season to fire Hoffenheim to the top of the standings.
However, he limped out of a friendly against Hamburg in La Manga in midweek and returned to Germany, where the extent of his injury was revealed.
The Bundesliga big-spenders will now begin their search for a replacement.
"We already had an idea of what kind of a striker we wanted and now we are focusing on the huge hole that Vedad leaves behind," said the club's general manager, Jan Schindelmeiser.
Coach Ralf Rangnick added: "The candidate can be a little older than Vedad, just as long as he has proven goalscoring qualities and fits in here both as a person and financially."
Money should not be a problem for Hoffenheim with owner Dietmar Hopp having already invested 25 million euros in new players.
Both Schindelmeiser and Rangnick are scouring the market for a replacement before the Bundesliga season resumes at the end of the month.
However, Schindelmeiser is aware it will not be an easy task.
"Which club sells their best striker in the middle of January?" he asked. "We will not pay any price."