Major League Soccer has invoked a clause in the agreement with its players that could lead to renegotiation of the collective bargaining agreement between the league and union.

The “force majeure” clause invoked by the MLS on Tuesday obligates the league and the MLSPA to negotiate modifications to the existing collective bargaining agreement in good faith for 30 days.

If an agreement on the modifications cannot be reached, the CBA agreed to in June when the league returned with the MLS is Back tournament could be terminated.

The players association had expressed concern over the league trying to reopen negotiations on the CBA following a season when MLS said its clubs lost “nearly $1 billion” due to the COVID-19 pandemic. MLS teams rely mostly on gameday revenue and the league estimated those were down about 95% across the league in 2020, and bigger crowds may not return until later in 2021.

A revised CBA proposal has not been issued by the league to the union, but is expected soon.

“Unfortunately, based on the assessment of public health officials, it is clear that the impact of COVID-19 and the restrictions on attendance at sporting events will continue into the 2021 MLS season,” MLS deputy commissioner Mark Abbott said in a statement. “We recognize the impact that the pandemic has had on our players and appreciate their efforts to restart and complete the 2020 season. But, like the other leagues in the United States and Canada, MLS needs to address the ongoing challenges caused by the pandemic and will engage in good faith discussions with our players about ways to manage the significant economic issues we are facing.”

The league and the union reached a five-year collective bargaining agreement last February, but it had not been ratified when the season was put on hold in March by the pandemic.

The sides renegotiated the deal in June ahead of the tournament in Florida, agreeing to a new one that included across-the-board pay cuts and reduced bonuses.

When the league returned to playing in its home markets following the Florida tournament, most games were played without fans or in front of small crowds due to attendance restrictions. The league also faced increased costs for testing and charter flights for all teams.

The 2020 season concluded on Dec. 12, with Columbus beating Seattle in the MLS Cup final.

Earlier this month, MLSPA executive director Bob Foose said the players association was concerned this was the direction the league would go and players may balk at a third contract negotiation in less than a year.

“After a 2020 season of extreme sacrifice, immeasurable risk to personal health, and a remarkable league-wide effort to successfully return to play, this tone-deaf action by the league discredits the previous sacrifices made by players and the enormous challenges they overcame in 2020,” the MLSPA said Tuesday in a statement.