Cesc Fabregas has been ruled out for up to four weeks with a thigh injury suffered during Barceona's win at Real Betis on Sunday.
Fabregas was on the pitch for only nine minutes before he had to be replaced by Alexis Sanchez. Barcelona later confirmed on their official website that he faced a lengthy stint on the sidelines.
"FC Barcelona's medical services have confirmed that Cesc Fabregas has torn the bicep femoris in his left thigh," a statement said.
"He'll be sidelined for three to four weeks. Therefore, he'll miss the team's last three games in 2012 - the two Liga matches against Atletico Madrid and Valladolid and the away leg of the Copa del Rey against Cordoba.
"He could also miss the first games of 2013, against Espanyol and the return leg of the cup at the Camp Nou."
Lionel Messi scored twice for Barcelona in the 2-1 win to beat Gerd Muller's record of 85 goals in a calendar year.
However, there were further injury concerns from the match as Carles Puyol was taken off at half-time with pain in his right leg.
Information from the Press Association was used in this report.