In the wake of Major League Soccer's announcement last month that Sacramento's expansion team is on indefinite hold, MLS commissioner Don Garber said the league has moved forward vetting alternative options for its 30th team.

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"Right now, there are other markets that we're looking at," Garber said on Monday. "I'm sure people are expecting that, whether that be Las Vegas or San Diego or whether it be Phoenix and we'll see how all those develop."

Garber did not provide any specifics about which of those cities might have a leg up -- all three currently have teams playing in the USL Championship -- and did not dismiss the possibility that Sacramento could still join the league if a new investment group emerges.

Rising costs associated with constructing Sacramento's planned stadium at the Downtown Railyards site was the primary factor that caused lead investor Ron Burkle to pull out of the agreement, adding another level of frustration for a city that has long pursued an MLS franchise.

Multiple sources have told ESPN's Jeff Carlisle that initial discussions have taken place between MLS and San Diego State University regarding the framework of a deal that would see an MLS expansion team play in 35,000-seat Aztec Stadium, which is projected to open in September 2022.

But Garber said the league will continue to work with stakeholders in Sacramento to salvage that bid.

"I'd call this expansion project there leading up to this season as a COVID casualty," Garber said. "But there's still a lot of energy in Sacramento, it's a good soccer market. The mayor is very focused on trying to put another ownership group together. We're going to work with him to see what can be achieved."

The league has also seen a lot of momentum, Garber said, in finding a new local investor to take over operations of Real Salt Lake, where the league has been in control of a looming sale since January. Dell Loy Hansen put RSL up for sale -- along with National Women's Soccer League side Utah Royals FC and the USL's Real Monarchs -- last August after MLS concluded an investigation of alleged racist and sexist behavior at the club.

"Great market, great brand, terrific facilities -- their training ground and Rio Tinto," Garber said about RSL."So I'm very optimistic of what will come to fruition hopefully by the end of the year in Salt Lake."

The MLS season begins Friday with a pair of games, starting with the Houston Dynamo FC and San Jose Earthquakes (8 p.m. ET, ESPN+).