Kyrie Irving basked in it — a crowd eager for his return, and his belief that he had won the battle he fought this season against vaccine mandates. When asked about the game, after Sunday night’s 119-110 loss to the Charlotte Hornets, he smiled.

He called it “historic” — being able to play for the Nets in Brooklyn. He said he had tried to stay grounded as he prepared for the warm reception he would receive.

“I don’t take for granted what happened tonight,” Irving said.

Just in time for baseball season, and for the N.B.A. playoffs, New York City created an exception to its private-sector coronavirus vaccine mandate that allows local athletes and performers to work in the city regardless of their vaccination status. That announcement on Thursday meant that Irving, who has declined to be vaccinated against Covid-19, could finally play at home.

“Now we can move on,” Irving said. “Now that everybody can move on, especially in the locker room. Limited distractions, no fear. Next game we’ll be better.”

His team, which began the season with championship expectations, is now fighting for a playoff berth. Irving’s return might give the Nets some stability, finally, after a season mostly without it. But in his first game back at Barclays Center, the Nets lost, and time is running out for them to develop the cohesion they will need to make a run this postseason.

“This is the situation that we’re in,” forward Kevin Durant said. “Put our heads down and go to work. I mean, you know, it’s a challenge. Everybody’s going through challenges this season as a team. This is what we’ve got in front of us.”

It had been nearly 10 months since Irving played in the Nets’ home arena. On Sunday night, the crowd of 18,166 people — a record number for a Nets game at Barclays Center — hailed him.

Before the game, a fan shown on the video board simply yelled, “Kyrie,” stretching out the final vowel. Irving got the loudest cheer of any player when the starting lineups were introduced.

Just before tipoff, he stood on the Nets’ logo at midcourt with the scoreboard camera fixed on him. The fans roared and Irving pointed up at them, turning to acknowledge each side of the arena.

“It was great to see him out there,” Durant said. “Good to see the fans excited for him.”

When Covid-19 vaccines became available, the N.B.A. created separate protocols, making it significantly easier for players who got a vaccine to stay active and participate in team activities. Although New York City’s law, and the N.B.A.’s insistence that teams follow local guidelines, had prevented Irving from playing at home, he was allowed to play on the road while observing stricter testing protocols.

The Nets at first said they weren’t interested in a part-time participant, but then changed their mind. Since Jan. 5, Irving has been a part-time player, suiting up for road games.

His stance against getting a coronavirus vaccine is unusual in the league. The N.B.A. and its players’ union now say 97 percent of players have been vaccinated and 75 percent have received a booster shot against the illness that has led to more than 40,000 reported deaths in New York City.

Recently, as the city began loosening restrictions, Irving’s teammates began itching for his return for home games. Adam Silver, the N.B.A. commissioner, said the law didn’t make sense because it allowed unvaccinated players on visiting teams to play.

On Thursday, suspiciously close to the start of baseball season, Mayor Eric Adams of New York announced an exception for local athletes and performers, setting up Irving’s Barclays debut.

“It’s not just the talent that Kyrie has, the continuity he provides playing at home,” Coach Steve Nash said. “But the amount of minutes and the amount of burden in the roles that guys have to assume when he’s not here.”

The date of his debut was not ideal. The Nets got home shortly before dawn on Sunday after playing Saturday night in Miami.

Irving missed his first five shots and was 6 for 22, but that didn’t quiet the crowd’s vocal appreciation for him.

“You feel the, kind of, anticipation,” Irving said.

He made only two of his first 17 shots, but was more efficient in the fourth quarter, making three shots in a row to tie the game at 104. He was fouled on his next attempt, and when he stood at the line, the crowd chanted his name.

Early this season, even without Irving, the Nets found themselves in the top quarter of the conference, with Durant and James Harden contributing to wins. But they lost Durant for 21 consecutive games because of a knee injury. Harden was traded to Philadelphia in February for Ben Simmons, who has yet to play for the Nets.

Only seven regular-season games remain for the Nets. They are now tied for eighth in the Eastern Conference and would rank ninth on tiebreakers if the season ended today. That is a seeding position that would require them to win two play-in games just to make it into the playoffs.

It was noted to Nash that the Nets might now have a starting five they can count on having for the rest of the season. He smiled wryly at the suggestion.

“We’re very hesitant to pretend that that’s just going to be the way it is,” he said.

Their season has been too unstable for Nash to rely on that.