Monaco striker Jan Koller is out for up to two months after injuring the same right hamstring that sidelined him during the World Cup finals this summer.
The Czech international record scorer hurt his leg during Monaco's defeat on penalties to Stade de Reims in a French League Cup match on Tuesday.
He said: 'Right away I knew it was bad. I think I will be out six to eight weeks.'
The 6ft 7in tall striker moved to Monaco on a free transfer from Borussia Dortmund over the summer after recovering from a serious knee injury he incurred last September.
He has since scored once in 11 appearances for his new club.
Koller was expected to be a force for the Czechs in the World Cup, and scored the team's opening goal of the tournament against the United States.
But just before halftime he fell to the pitch in a heap, even though he was not touched by anyone near him.
Clutching his right leg, Koller was stretchered off the field and did not return as the Czechs crashed out during the group stage.
