Lionel Messi will miss Barcelona's exhibition games in the United States against Napoli after leaving his first preseason training session with the club because of a strained right calf.

The Spanish champion says Messi withdrew from Monday's training session because of "discomfort in his right leg." The club did not say when it expects him to be fit again.

Barcelona plays on Thursday at Miami Gardens, Florida, and on Saturday at Ann Arbor, Michigan.

Messi had been on vacation since Argentina finished third in the Copa America last month.

Barcelona's Spanish league opener is at Athletic Bilbao on Aug. 17.