Barcelona have been rocked by the news that Lionel Messi's thigh injury is more serious than initially thought.

The Argentina forward has not played since tearing a muscle during the Champions League last 16 tie against Chelsea in early March.

The teenager returned to training earlier in the week, only to suffer a setback which doctors initially thought would only prevent him from playing against Villarreal on Friday and in the first leg of the Champions League semi-final against AC Milan next week.

However, Argentina's national team doctor Donato Villani said: "It's a complicated sort of tear. He's going to need three or four more weeks' treatment.

"In my opinion he will only be ready to play one more game this season and that will be the Champions League final."

Should Messi fail to recover in time to play again for Barcelona this term, Argentina coach Jose Pekerman will face an awkward decision about the youngster's participation in the World Cup finals.