Franck Ribery has suffered ligament damage to his right ankle in an ill-timed injury blow for embattled Serie A side Fiorentina.
The Viola confirmed the setback after the 36-year-old was forced off in the first half of Saturday's 1-0 loss to Lecce.
Panagiotis Tachtsidis' sliding challenge left the experienced winger in considerable pain and he had to be helped from the field.
Precisely how long he will spend on the sidelines remains to be seen, but Fiorentina can little afford to do without the former Bayern Munich star following a third successive defeat.
A club statement read: "Ribery underwent tests after spraining his ankle. They revealed a Grade I/II tear of the medial collateral ligament of his right ankle. He has begun treatment and his condition will be re-assessed soon."
The loss to Lecce left Fiorentina nine points outside the top six after 14 games.
Newspaper reports in Italy suggest Vincenzo Montella is under pressure to save his job amid rumours Gennaro Gattuso and Cesare Prandelli could take over.