Daniele De Rossi will miss Roma's Champions League trip to CSKA Moscow, and possibly matches beyond that, head coach Eusebio Di Francesco confirmed.
De Rossi was injured in the first half of Roma's last match, a 1-1 draw away to Napoli, in what was his 450th Serie A appearance.
And the club captain will miss Saturday's trip to Fiorentina as well as the Group G game away to CSKA four days later, and possibly more matches beyond.
"De Rossi won't be involved against Fiorentina or CSKA - and he may miss the Sampdoria game too," Di Francesco told a news conference.