Borussia Dortmund midfielder and Poland captain Jakub Blaszczykowski has been ruled out for the rest of the season with a torn anterior cruciate ligament in his right knee.
The Bundesliga club says a scan Sunday morning confirmed the extent of the injury which happened early in Saturday's 2-2 draw at home with Augsburg.
Blaszczykowski, who will undergo an operation in the coming days, told the club's website, "Nothing can throw me off so quickly. I will do everything to return to the pitch stronger than ever before."
Dortmund doctor Markus Braun says the 28-year-old player can expect to return to training after the summer break.
Dortmund has already had to cope with long-term injuries to Ilkay Gundogan, Mats Hummels, Lukasz Piszczek and Neven Subotic this season.
Poland failed to qualify for this year's World Cup in Brazil.
Information from The Associated Press was used in this report.