MADRID, April 13 (Reuters) - Barcelona forward Lionel Messi will miss both legs of the Champions League semi-final against AC Milan and will return home to Argentina for treatment on his thigh muscle injury.
The club said the 18-year-old international will fly out next Tuesday and will be treated by club medical staff.
Messi has been out of action since the beginning of March when he tore a thigh muscle during the second leg of a 3-2 aggregate victory over Chelsea in the first knockout round.
'He needs more time,' said Barca coach Frank Rijkaard. 'It might be good for him to have a change of scenery and recover completely. He will return when he has recovered.'
Argentine national team doctor Donato Villani said the player could be out of action for a further month.
'It's a complicated sort of tear,' Villani was quoted as saying in the Spanish media on Thursday. 'He's going to need three or four more weeks treatment.
'In my opinion he will be ready to play only one more game this season and that will be the Champions League final.'
Barcelona meet Milan at the San Siro on Tuesday before hosting the return match at the Nou Camp on April 26.
Messi has been one of Barca's most exciting players this season. The latest injury set-back means Sweden striker Henrik Larsson is likely to retain his place in the starting line-up for the Milan match.