Roma could be without Brazilian defender Juan for almost two months after he limped out of the derby loss to Lazio on Sunday.
The stopper was replaced in the 76th minute after complaining of a problem with his right knee during the 2-1 defeat.
The South American underwent an MRI scan earlier today which showed some ligament damage.
Although surgery is not necessary, Roma have confirmed that the former Flamengo and Bayer Leverkusen player will be sidelined for around 45-50 days.
Boss Luis Enrique is already short of centre-backs given that Nicolas Burdisso was ruled out for the rest of the season last autumn.
Juan’s injury may now see midfielder Daniele De Rossi used more regularly as a centre-back option.