Roma midfielder Alessandro Florenzi faces a lengthy spell on the sidelines after rupturing the anterior cruciate ligament in his left knee in Wednesday's 3-1 Serie A win over Sassuolo.
The Italy international was stretchered off with five minutes left on the clock, Francesco Totti taking his place on the pitch.
After undergoing a series of tests, Roma have now announced Florenzi requires surgery.
"Alessandro Florenzi underwent diagnostic tests during the night which revealed he has ruptured the anterior cruciate ligament in his left knee," a statement on the club's official website reads.
"Florenzi will undergo surgery on Thursday."
Florenzi has been a key figure for Roma this campaign, making 13 appearances in all competitions, in which he scored once.
The 25-year-old captained Roma at the start of the season in the absence of Totti.