Inter have confirmed that Gary Medel's knee surgery on Thursday was a success and he is expected to be out for around two months.
The Chile international was forced off after just 37 minutes in Sunday's derby clash with AC Milan, suffering damage to his lateral meniscus, which makes up part of the knee joint.
Inter refused to set a specific timescale for his return, but he is expected to be out at least until early January, meaning he will miss Serie A contests against the likes of Fiorentina, Napoli and Lazio.
A brief club statement read: "Gary Medel underwent successful arthroscopic surgery in Barcelona on Thursday.
"The lateral meniscectomy procedure was performed by Dr Ramon Cugat at the request of FC Internazionale. Club doctor Alessandro Corsini was in attendance during the operation."