It makes sense that MLS teams were active globally during FIFA’s winter transfer window, because it occurs in the MLS offseason when clubs are busy building rosters. However, some international clubs in the thick of their seasons may be unwilling to part with players — which has helped spur increasing calls to shift the MLS season.

Major League Soccer's 30th season kicks off this weekend with fans still clamouring to see its biggest star, Inter Miami's Lionel Messi, and the addition of San Diego FC, the league's 30th club. Messi led Miami to the top of the regular season standings last year before the club suffered a stunning defeat in the playoffs at the hands of Atlanta United.

Major League Soccer's 30th team kicks off its first season Sunday with a match on the road against defending league champion LA Galaxy.