Napoli striker Arkadiusz Milik could be out for several months after suffering an anterior cruciate ligament injury while on international duty with Poland.
Milik, 22, was forced to come off at half-time during his nation's 3-2 win over Denmark on Saturday after sustaining the injury and underwent a series of tests after the final whistle.
Poland's media officer Jakub Kwiatkowski revealed after the game that Milik had damaged his anterior cruciate ligament and may face a lengthy spell on the sidelines.
"Arek Milik has undergone tests on his injured knee, which have shown damage to the anterior cruciate ligament," Kwiatkowski posted on Twitter. "Arek will return to Napoli on Sunday. He is likely to have to undergo surgery and could be out for several months."
- Official SSC Napoli (@sscnapoli) October 9, 2016
Napoli have yet to confirm the extent of the injury but said that Milik will undergo further tests in Naples.
"The striker will return to Italy after the injury suffered with Poland," a club statement read. "Arkadiusz Milik is expected during the day in Italy where he will be subjected to visits and diagnostic tests to ascertain the extent of the injury."
Milik joined Napoli from Ajax in the summer for a reported €32 million and has so far scored seven goals in nine appearances for the Serie A club.