D.C. United players hopped off a bus and into the biting cold Monday morning in Arlington for the first formal preseason workout. The focus at Long Bridge Park was on building fitness, not to mention staying warm, before camp moves indoors Tuesday and to Florida next week.

As the preseason commences, however, a cloud of uncertainty remains about whether MLS and the players’ union will reach a labor deal in the coming weeks.

The current pact expires Jan. 31, and although the 26 teams are likely to continue conducting preseason business as usual under the previous terms, it’s hard to imagine the season starting on schedule Feb. 29 without an agreement.

“We are at a spot now where things are moving forward with the CBA,” said midfielder-defender Russell Canouse, United’s union representative. “But there is still a lot that needs to get done before we get to a deal. I am really neutral right now. We’ll see. These next coming weeks are crucial to getting a deal done. I am not really optimistic or pessimistic. I just want to see how things progress.”

MLS and the MLS Players Association have met regularly for months and largely have kept details in the bargaining room. Key issues include compensation, free agency and off-day considerations, such as chartered flights.

Canouse said solidarity among the players is strong and communication among team reps, the workforce and the MLSPA’s executive board has strengthened the effort. Until there is a breakthrough or breakdown, the players said they not are distracted by the negotiations.

“Everyone is concentrating on training and excited to come back and play,” midfielder Felipe Martins said. “That is going to continue until something happens. This shouldn’t be a distraction to anybody because we are getting paid to work every day.”

>> Peruvian midfielder Edison Flores, United’s major winter acquisition, is in Washington but not allowed to participate in full training until his visa issues are settled. At some point, he will return to Peru for final processing.

Estonian forward Erik Sorga, who for now is under contract with second-division Loudoun United, is in the visa process as well and might be able to report to training camp next week.

Goalkeeper Bill Hamid and midfielder Paul Arriola are with the U.S. national team through a Feb. 1 friendly against Costa Rica in Carson, Calif.

>> Center back Aaron Maund, who started 82 MLS matches over seven seasons before playing for second-tier Charlotte last year, was invited to camp. With only three returning center backs (Steven Birnbaum, Frédéric Brillant and Donovan Pines), United is seeking reinforcements.

There is also need for competition at left back. Joseph Mora is the incumbent. Oniel Fisher and Chris Odoi-Atsem are candidates at right back, and Canouse is also an option after starting there late last season. Canouse said Monday that “I am hoping to be back in the middle of the park.”

Fisher missed all of 2019 recovering from a knee injury, and Odoi-Atsem made three appearances after recovering from cancer treatment. United officials said they remain in the domestic and international markets for players.

“We could use a lot of depth, honestly, everywhere right now,” Birnbaum said. “We are a little thin, and I’m sure the front office is working on it. There’s going to be more guys coming and going the next month and a half. I’m sure the team is going to change quite a bit.”

>> Goalkeeper Andrew Verdi, United’s third-round draft pick from Michigan, did not report to camp. He chose to continue pursuing his degree, United officials said.

Verdi would have been a candidate for a contract with Loudoun United. First-round pick Simon Lefebvre, a French goalkeeper from Temple, is in camp and seems likely to land at Loudoun. Second-rounder Josh Fawole, a forward from Loyola (Md.), reported to camp and also seems to be a Loudoun candidate.

>> With Wayne Rooney gone, United needs a captain. Coach Ben Olsen has not decided on a replacement.

Birnbaum handled the role before Rooney’s arrival in 2018. Several others are worthy candidates, Olsen said.

“A lot of guys don’t need armbands to lead, a title to be a leader,” Martins said. “Many guys are going to lead in different ways.”

>> On a frigid morning, Martins was in shorts for the outdoor session.

“Cold is mental,” he said with a shrug.

Martins is from Brazil but has played in Switzerland and Canada.

United will train the rest of the week indoors at the St. James complex in Springfield before moving operations Sunday to Clearwater, Fla. The preseason opener is Tuesday, Jan. 28 against Montreal at the University of South Florida.