The Argentine is a doubt for this weekend's clash with Malaga after limping out of the 1-1 Super Cup first-leg draw with Atletico Madrid.
The Argentine star was withdrawn at halftime of Wednesday's Spanish Super Cup first leg with Atletico Madrid after complaining of discomfort during the opening 45 minutes.
Tests conducted by the club's medical staff have since confirmed a hematoma affecting Messi's left thigh muscle, with the Catalan side confirming via its official website that the 26-year-old is a doubt for this weekend's clash with Bernd Schuster's side.
The news marred a spirited fightback from Barcelona in Wednesday's game at Vicente Calderon, in which Neymar headed home his first competitive goal for Gerardo Martino's side.
Martino has already made it clear that Messi will need to be rested at specific points during the 2013-14 campaign in order to avoid a repeat of the leg injury which blighted the end of last season for the Argentina international.