Bologna defender Cesare Natali is facing up to six months on the sidelines after damaging knee ligaments.
The 33-year-old suffered the injury during the Serie A game against former club Fiorentina on Sunday.
A statement on Bologna's official website confirmed that the Italian will require surgery on his right knee.
Natali only left Florence in the summer, signing a two-year contract with the Rossoblu for his second spell at the club.
The former Italy Under 21 international had spent three years at the Stadio Artemio Franchi but it was a nightmare return with Bologna also losing the game 1-0.