The opening weekend's 14 matches include Charlotte's debut match at DC United, with the league growing to 29 teams next year with St. Louis and in talks with Las Vegas to become the 30th MLS squad.
"We've got to pause and get our 30 teams up and going and then we can decide if Major League Soccer is going to expand beyond 30," MLS commissioner Don Garber said. "There's no timetable for any decision beyond 30 teams."
But MLS hopes to continue its growth when Canada, Mexico and the United States co-host the 2026 World Cup.
"There's really no limit to where Major League Soccer can go in the years ahead," Garber said. "By all measures the progress has been remarkable, but the most important period of growth and opportunity is really in the years ahead leading up to the World Cup."