Barcelona, Spain – Barcelona says Lionel Messi has strained his right calf and will not travel to the United States for two preseason games. including Saturday's match at Michigan Stadium.

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’s first official match of the season is its Spanish league opener at Athletic Bilbao on Aug. 17.

Before that, the team will visit the U.S. and play a friendly against Napoli in Miami on Thursday. It will then play another game against the same Italian opponent at the University of Michigan on Saturday at 5 p.m.

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

FC Barcelona did release its roster Monday for its U.S. trip.

1. Marc-Andre ter Stegan

2. Nelson Semedo

3. Gerard Piqué

4. Ivan Rakitic

5. Sergio Busquets

6. Jean-Clair Todibo

7. Philippe Coutinho

8. Arthur Melo

9. Luis Suárez

11. Ousmane Dembélé

12. Rafinha

13. Neto

15. Clement Lenglet

16. Moussa Wague

17. Antoine Griezmann

18. Jordi Alba

19. Carles Aleñá

20. Sergi Roberto

21. Frenkie De Jong

22. Arturo Vidal

23. Samuel Umtiti

24. Junior Firpo

25. Iñaki Peña

27. Carles Pérez

28. Riqui Puig

29. Abel Ruiz