The Major League Soccer board of governors voted to align with the international soccer calendar by shifting the regular season to a summer to spring campaign beginning in 2027.
As opposed to most international leagues, MLS currently plays on a February to November calendar.
"The calendar shift is one of the most important decisions in our history," MLS commissioner Don Garber said in a news release. "Aligning our schedule with the world's top leagues will strengthen our clubs' global competitiveness, create better opportunities in the transfer market, and ensure our Audi MLS Cup Playoffs take center stage without interruption.
"It marks the start of a new era for our league and for soccer in North America."
The change would see the season kick off in mid-July and run through the spring, with Decision Day in April and the MLS Cup playoffs in May. MLS would allocate a winter break to prioritize player recovery, pausing action from mid-December to early or mid-February.
More than 90% of games are expected to be played in the footprint the league currently employs.
A shift in the upcoming calendar would see MLS coincide with the international transfer windows, facilitating the clubs' ability to take part in the global transfer market. The current calendar sees the MLS primary transfer window run from Jan. 31 to April 23, while most international leagues do player transfer during a traditional summer window.
MLS will run a shortened season in 2027 from February to May, where an MLS Cup champion will be crowned before the league officially shifts to a summer/spring calendar.
"We will have an MLS regular season. We'll have a regular season that crowns an MLS champion, we will award Concacaf Champions Cup spots based on performance in that MLS season," said Nelson Rodriguez, MLS executive vice president of sporting and competition. "We expect the U.S. Open Cup, the Canadian championship to continue to exist and we'll also have that MLS season serve as a qualifier for Leagues Cup.
"Less matches, less overall League season matches, but with a full playoff and an MLS Cup championship."
Nelson later confirmed there was a vote on the competition format, though details of the changes continue to be discussed.
While the board of governors approved the switch, the league is still working out the details with the MLS Players Association and could hit a stumbling block there. Rodriguez said there was "very good dialogue" with the MLSPA. Another source said the discussions were "teetering."
Sources told ESPN that the primary issues for the MLSPA was the league's unwillingness to commit to hard dates in terms of the schedule changes, as well as the length of the offseason. If the offseason was too short, it could make player movement via free agency -- something the MLSPA has fought for through multiple collective bargaining agreements -- difficult.
Negotiations for the last CBA, ratified in 2021, were contentious in that the league twice forced a renegotiation that rolled back a considerable amount of gains the MLSPA achieved at the bargaining table.
The first rollback resulted in the MLSPA giving up $150 million over the life of the deal to avoid pay cuts. MLS also succeeded in extending the term of the CBA for an additional two years through 2027.
More recently, the two sides butted heads over bonuses for the FIFA Club World Cup. It's no surprise then that the union is attempting to exert some leverage in its discussions with MLS.
Garber previously teased the possibility of the change in calendar, saying the alignment with international leagues made sense. Though the board of governors failed to pass the motion during the summer's meeting, the topic continued to be discussed before finally being confirmed Thursday.
"We're not making any announcements today, but we continue to do an enormous amount of work with our fans, with our partners, with all of our chief soccer officers and with our clubs, to get ourselves closer to the point where we're able to make that decision," Garber said in July. "But we believe that alignment is something that makes sense."
ESPN's Jeff Carlisle contributed to this report.