Barcelona forward Lionel Messi is set to sit out the first leg of the Champions League semi-final against AC Milan because of a thigh injury.

The Argentina international has not played since tearing a muscle in his right thigh during the second leg of Barca's last 16 tie against Chelsea on March 7, but returned to training last week in the hope of being ready to face Milan.

However, the 18-year-old suffered a recurrence of the problem in training and has been advised to rest for the next few days, ruling him out of Friday's Primera Liga clash with Villarreal and the trip to Italy on April 18.

Messi is expected to be a central figure in Argentina's bid for success at the World Cup finals and his continuing absence must be a concern for national coach Jose Pekerman.