D.C. United midfielder Luciano Acosta maneuvers against Toronto FC in October at Audi Field. (John McDonnell/The Washington Post)

CLEARWATER, Fla. — Luciano Acosta will remain with D.C. United, at least for the immediate future.

A whirlwind of negotiations on the final day of the transfer window ended Thursday without an agreement between the MLS organization and Paris Saint-Germain, killing a proposal that would have sent the electrifying Argentine playmaker to one of the wealthiest and most ambitious soccer clubs in the world.

United expected to receive a formal offer of around $10 million, one person close to the talks said. If that figure had been put forth, the MLS team was prepared to accept it.

But that same person, who requested anonymity because he was not authorized to reveal details, said PSG offered $7 million, raised it to $8 million and suggested making up the difference if Acosta met incentives. United, the source said, balked. At that point, PSG walked away.

Acosta — who had traveled to Paris overnight for what he believed would be a career-changing move — was described as being “upset” about the talks breaking down.

United General Manager Dave Kasper had also flown to Europe on short notice, arriving in London for talks with one or two Premier League clubs — those discussions never accelerated — before traveling to Paris.

Kasper was not available to comment. Other United officials declined to speak about the busted negotiations.

United has received inquiries about Acosta for months, but none were worth considering until this week, when Saudi club Al-Hilal offered $7.5 million, one source said. United rejected it. As the European deadline approached, interest intensified in the past 24 hours.

The transfer would have yielded the largest windfall in club history — the previous high was $3 million in 2013 when homegrown player Andy Najar was sold to Anderlecht in Belgium — and allowed Acosta, 24, to test himself on one of the biggest stages in soccer. His salary would have soared into the millions after earning $652,000 last year.

With the transfer window closed, Acosta cannot move to a European team until the summer, at the earliest.

In the final year of his contract in MLS, Acosta might end up signing a new deal with United before the season opens March 3. D.C. officials have been engaged in talks with Acosta’s agent for several weeks and proposed a long-term, guaranteed deal that would make him among the highest-paid players in the league.

However, if his heart is set on Europe, Acosta could decline to sign a new pact and plan to leave United after the 2019 season. Within six months of a deal expiring, Acosta could pursue a pre-contract with a new team. (If he signed one, he wouldn’t leave United until the season ended, but D.C. would not collect a transfer fee.)

It’s also possible a club from overseas extends an offer this summer. But with Acosta’s deal expiring later in the year, an interested party would probably wait until he became a free agent to avoid paying a transfer fee.

Acosta presumably will rejoin his teammates in Florida soon, but after the chaos of the day and the subsequent disappointment, United might need to give him space before requiring him to resume workouts. United will play its first preseason friendly Saturday.

Acosta enjoyed a breakout season last year, finishing second in the league in assists, earning a place on MLS’s Best XI all-league team and playing the type of entertaining soccer that United had waited for — but previously seen in sporadic bursts — since his arrival in 2016.

He and English star Wayne Rooney forged one of the league’s most lethal attacking partnerships and helped D.C. surge from last place in the summer to a playoff berth.

When Acosta departed for the airport Wednesday night, members of the delegation saw him off and wished him luck. One person said Acosta was “shaking with excitement.”

The team went about business as usual Thursday with two training sessions.

After the morning workout, Rooney said PSG’s interest in Acosta was “a massive opportunity for him. I think everyone here will be happy for him. Obviously, it would be a loss to us. It’s not nice to lose a player of his ability, but for him and for his career, it’s a great opportunity. He is certainly good enough to play there.”

United notes: Defender Akeem Ward, a first-round draft pick from Vienna, Va., and Creighton University, signed with the team. Terms were not disclosed.

Read more:

‘The country needs to change’: Venezuela is on Junior Moreno’s mind at United camp

Debris believed to be from missing plane carrying Emiliano Sala turns up on French beach

Neymar out 10 weeks with foot injury, will miss Manchester United games

A few good minutes with Richie Williams, Loudoun United’s first head coach