The 33-year-old has already informed the club that he wants to leave this summer.
Messi is looking to exercise a clause, which allows him to leave the Nou Camp as a free agent, but Barca is of the opinion that the timeline has passed for him to do so.
Ahead of a possible legal battle with the LaLiga giants, Messi’s representatives have advised him against doing anything that could give the club extra ammunition in the courtroom.
The player will, therefore, turn up on Monday, despite previous indications that he wouldn’t.
Messi will then undergo preseason tests and drills