MADRID, Dec 16 (Reuters) - Barcelona forward Lionel Messi will be out of action for up to five weeks after tearing a thigh muscle in his left leg.
The Argentina international had to be substituted on Saturday just before halftime of his side's 3-0 victory away to Valencia in the Primera Liga, having helped set up the first two goals for Samuel Eto'o.
Tests by club doctors on Sunday confirmed the original diagnosis, which rules him out of the top-of-the-table clash with league leaders Real Madrid next weekend.
Barca are second a point behind their arch-rivals, who play Osasuna at home later on Sunday.
Messi is Barca's top scorer in the league with eight goals, and could miss up to seven league and King's Cup matches before returning, the club said.