Minnesota United on Tuesday signed defenders Brent Kallman and Callum Montgomery, midfielder Jacori Hayes and backup goalkeeper Adrian Zendejas to new contracts.

Hayes was acquired about this time last year in a trade with FC Dallas. Now 25, he started six of 11 games he played for the Loons last season. In an Instagram post, he called himself happy to return this coming MLS season that's scheduled to begin April 3 and hoping to build off a 2020 season in which his team lost the Western Conference final 3-2 at Seattle.

Kallman, the longest-tenured Loon dating to 2013 and their pre-MLS days, was loaned to El Paso last August and returned in early October.

Montgomery, the fourth overall pick in the 2019 MLS SuperDraft, was acquired in a December trade while a September trade with Nashville brought Zendejas to help the Loons' injury-depleted goalkeeping unit at the time.

Minnesota also has obtained defender Jukka Raitala from Montreal in a trade and added three college players in the 2021 SuperDraft. The team likely will add two much-needed strikers, including one on a Designated Player deal.

The Loons also have discussed bring back captain Ozzie Alonso for this season in a role that could keep him with the team after his playing days are done. They continue to seek clarity on two-time MLS Defender of the Year Ike Opara's potential return after he hasn't played a game since last March.

MLS players are set to begin training Feb. 22, but remain in labor negotiations with the league.