The Argentina international was brought off midway through the first half with a mystery problem as his recent fitness issues persistLionel Messi was withdrawn early in Barcelona's visit to Betis on Sunday as his recent injury woes continued.
The Argentine, 26, started in the central role for Gerardo Martino's men in the trip to the bottom-of-the-table Liga side but only lasted 21 minutes - the shortest he has ever featured for the club after being picked in the starting line-up.
Andres Iniesta was brought on in Messi's place, with the four-time Ballon d'Or hobbling off the pitch with no confirmation yet regarding how long the attacker will be out for.
Barca have confirmed that the problem is a hamstring injury to Messi's left leg, with further tests to assess how long he will be out to be undergone on Monday.
He is now a major doubt for Argentina's friendlies in the upcoming international window against Ecuador and Bosnia & Herzegovina.
Messi broke Gerd Muller's record for goals scored in a calendar year in the fixture last season but has now gone five Liga games without a goal.
Barca ultimately won the clash with Betis 4-1 without the forimable forward - Neymar, Pedro and Cesc Fabregas (twice) getting on the scoresheet, with a stoppage-time consolation from Jorge Molina.
Following the match, the Catalans also confirmed that Fabregas was suffering with knee discomfort and would undergo tests soon too.