The Argentine failed to re-appear in the second half of the Blaugrana's first-leg clash against PSG after giving his side the lead moments beforehand
The club confirmed that the Argentine had damaged his right hamstring in Paris and that he will undergo tests on Wednesday to assess the full extent of his problem.
"Messi sustained an injury to his right hamstring. He will undergo further tests on Wednesday to determine the extent of the injury," read their statement.
The Argentine appeared to have suffered the muscle strain towards the end of the first half, with the attacker hugging the touchline and showing limited movement in the closing moments while talking with manager Tito Vilanova.
The Barca boss then chose to substitute the 25-year-old during the break, replacing him with Cesc Fabregas.
Messi had already put the Blaugrana ahead in the 38th minute, latching onto a lofted Daniel Alves' pass before striking the ball low past PSG keeper Salvatore Sirigu.