BOSTON — Josh Hart has experienced quite a bit. He won a national championship at Villanova. He played alongside LeBron James with the Los Angeles Lakers. He reached great heights and scrambled for minutes. But Hart got a dose of something new at the start of this N.B.A. season with the New Orleans Pelicans: relentless positivity.

It hardly mattered that the Pelicans had lost 12 of their first 13 games, or that they were scuffling through a series of blowouts, or that the team’s fans seemed preoccupied with the one player — Zion Williamson — who was absent from the lineup. No matter the circumstances, Willie Green, the team’s first-year coach, was going to remain upbeat.

“I think he was almost overly positive,” Hart, a fifth-year guard, said in an interview. “But this is a new group with a lot of young players, and we knew it was going to take time.”

That process, as evidenced by the Pelicans’ 104-92 loss to the Celtics on Monday in Boston, is continuing. But there has been progress. Since their brutal start, the Pelicans have gone 15-16 behind the efforts of unsung players like Hart, who, at 6 feet 5 inches, defends and rebounds, and has joined his teammates in focusing on what they can control.

“Obviously, we want Z to get back as quickly as he can and get 100 percent,” Hart said of Williamson. “But we can’t sit here and be like, ‘We’ve got to keep the ship afloat in hopes of a Zion grand return.’ That’s just not the mentality to have. The mentality is: We’re not going to have him for the season. That’s how we’re looking at it, and we’ve all got to step up and hoop and take advantage of our opportunities. And if he comes back? Perfect, we’ll be even stronger.”

Williamson, a first-time All-Star last season and one of the N.B.A.’s most explosive players (when in uniform, which is increasingly rare), has had a series of setbacks since he had off-season surgery to repair a fracture in his right foot. A planned return to practice in December was abandoned when he reported soreness. Medical imaging revealed what the team assessed as a “regression” in the healing process, and he has since been rehabilitating in Portland, Ore. He has yet to play in a game this season, and there is no timetable for his return.

“He’s still recovering, still trying to get healthy,” Green said on Monday.

It is a credit to Green and his players that the Williamson story line has not ballooned into something bigger. Winning a few games has helped. But so, too, has Green’s approach.

“I go back and forth sometimes myself on how much positivity I should show,” Green said. “But there have been studies. If you show people positive ways in which to do things versus the negative, their growth is tremendous. And it just happens to be a part of who I am. It’s not like I’m not holding them accountable. But I would prefer to be positive.”

Hart said he did not feel especially valued last season under Stan Van Gundy, who was then the team’s coach. At times, Hart said, it felt like his only job was to stand in the corner and shoot the occasional 3-pointer. As the losses piled up, so did the bad vibes, Hart said. (He recalled a teammate being yelled at for calling a timeout after he dived for a loose ball.)

Van Gundy was fired after the Pelicans went 31-41 in his lone season as the team’s head coach. Hart, meanwhile, waded into restricted free agency after having missed the team’s final 25 games with a hand injury. Still, he was hopeful that he would receive interest from teams around the league. Those lucrative offers never materialized. He wound up signing a three-year extension with New Orleans. The deal could be worth as much as $38 million, but it comes with a big caveat: Only the first year is guaranteed.

“I know it’s very easily tradable,” Hart said, “so that’s always in the back of your mind.”

Hart had been hoping for more security, and, for the first time in his adult life, he took a break from basketball over the summer. He got married. He spent some time away from the game, banking on the belief that distance would give him fresh perspective. He also began preparing to play for yet another head coach — his fourth in five seasons. Hart acknowledged that cycling through so many philosophies and management styles can take a toll on a young player, especially one trying to find his niche.

“Some coaches are positive, and some are negative,” he said. “Some keep it real with you, and some kind of don’t.”

Hart said he was still feeling “skeptical” about his place in the organization when he met Green for the first time over dinner before the start of training camp. Green, a former assistant with the Warriors and the Suns, said he approached the meeting with an agenda. First, he wanted to listen: What had happened with Hart over the summer? What were his frustrations? How could he help? Second, he wanted to convey that he loved Hart’s competitive nature — “He has made every team he’s played for better,” Green said — and viewed him as a leader.

“I walked away feeling encouraged that he wasn’t going to limit me or put me in a box, that he was going to let me play the game the way I love to play it,” Hart said. “For a basketball player, that’s what you want to hear — that you have the confidence of your coach.”

Hart is assembling his most complete season as a pro, averaging 13.1 points, 7.5 rebounds and 4.3 assists while shooting a career-best 51.5 percent from the field.

“I believe in them,” Green said of his players. “Even when it doesn’t look great, I know we’ll get there.”