The medical staff at the Corinthians soccer team confirmed on Thursday that Ronaldo will be forced to sit out of their upcoming blockbuster match against cross-town rival Palmeiras.

Ronaldo scored his first goal of the season in Wednesday's fourth round match of the Sao Paulo state championship against Mirassol but also injured his right knee ligament.

The main concern of the coaching staff is whether Ronaldo is recovering right in time for the team's debut in the 2010 Libertadores Cup. The team will host the winner of Junior Barranquila and Racing-URU on February 24.