Four days before Major League Soccer's current transfer window closes, Minnesota United traded captain Francisco Calvo to the Chicago Fire on Friday for at least $400,000 in allocation money that it can spend on acquiring players.

The trade came nine days after Calvo, a 2018 MLS All Star and World Cup participant for his homeland Costa Rica, was suspended for one game because of a red-card violation April 19 against Toronto. He sat out the Loons' next game — a scoreless draw with L.A. Galaxy — and was neither a starter nor sub in their 1-0 victory over D.C. United on Sunday.

At the time, United coach Adrian Heath termed Calvo's frustrated kick at an opponent late in the Toronto game "silly." On Sunday, he explained the decision to keep Calvo out of the first 18 players against D.C. United, saying he didn't want "negativity" around a team that had just shut out L.A. Galaxy. Heath kept the same starting lineup, without Calvo in it.

On Friday, Heath and United Sporting Director Manny Lagos called the trade a long time coming. Lagos said it had "zero" to do with Calvo's suspension or its aftermath.

"These moments seem sometimes quick," Lagos said, "but the reality is we discuss the right fit, the right time, the right place. That has to be more than just a weakened moment."

The trade gives United financial flexibility and deals a player who prefers to play center back rather than left back, where he was needed this season. The Loons play on with new starter Eric Miller and rookie Chase Gasper, among others, at that spot.

Francisco Calvo (right), who was traded Friday, said he was happy to be part of the Loons’ debut at new Allianz Field.

Expect veteran Ozzie Alonso to assume Calvo's captaincy.

In a social media post, Calvo thanked the team as well as United fans for their "love and support."

Calvo, whose candor led him to criticize what he felt was a lack of respect given to the Loons last year, said in a Twitter post that it was "an honor to have begun our MLS journey together and to serve as your captain. I was a part of some great moments that I will never forget, like the opening of our new stadium. I have nothing but great things to take with me."

Heath called Calvo a "model professional" and wished him well. United plays at Chicago next Saturday.

"These are never done with anything personal," Heath said. "These are done for what we think is the right move for us. Francisco made it aware he wanted to play center back, and we think we're OK there. We decided it was the right thing for us at this moment in time."

United will receive allocation money from Chicago that it can spend in other player transactions. It'll get $100,000 in general allocation money (GAM) and $50,000 in targeted allocation money (TAM) in 2019 and $100,000 in GAM and $150,000 in TAM in 2020. The funds are provided by the league to teams.

GAM is considered more valuable than TAM because it can be used in more ways to manipulate a team's salary-cap spending.

United made a trade with the Galaxy to acquire more GAM and balance the amounts it has of each fund on Thursday. Lagos called that trade unrelated to the Calvo deal and said it's "unlikely but not impossible" the team will spend money from either trade by Tuesday. The next transfer window is in July.

The Loons could receive an additional $125,000 in TAM if Calvo reaches certain performance thresholds with Chicago. More importantly, United will receive what Lagos called a "significant portion" of a transfer fee if the Chicago Fire someday sells him to another team worldwide.

"In more ways than one, we wish him well to do well," Lagos said.

Heath flew to Calvo's native Costa Rica to convince him that he should sign with United in December 2016 and leave his homeland Saprissa club.

Named captain when the Loons' first MLS-era captain Vadim Demidov fell out of the starting lineup, Calvo started all 60 games in which he played during his two-plus seasons in Minnesota.

Last August United traded fan favorite Christian Ramirez near the end of a summer transfer window to LAFC for at least $800,000 in allocation money.

Loons midfielder Miguel Ibarra called Calvo a "great teammate" and "great friend to everybody." Ibarra and his teammates know well anything can happen when a transfer window is about to close.

"It happened to Christian last year, it can happen to anybody," Ibarra said. "We knew maybe some moves might happen."

United acquired defender Ike Opara in January from Sporting Kansas City for at least $900,000 in TAM.

"You don't really know with all this TAM, Spam, jam whatever nonsense it's called sometimes," Opara said. "It's hard to really figure out what your market value is at times when there's so many figures in this league. You just show up to where you're going and make sure you do what you need to do."