Lionel Messi is in doubt for Barcelona's Champions League match against Inter Milan on Tuesday due to a leg injury.

The Argentina forward was substituted in the 75th minute of Barcelona's 1-1 draw at Athletic Bilbao on Saturday because of a problem in his left thigh. Messi was scheduled to undergo medical tests on Sunday.

Barcelona coach Pep Guardiola says his "first feelings are not very good" about Messi playing in the group game against Inter.

Messi could also be a doubt for Sunday's "clasico" match against Real Madrid, which leads the defending Spanish champions by one point in the standings.

Barcelona is also missing striker Zlatan Ibrahimovic due to a hamstring injury and three regulars to swine flu.