Gordon Hayward and his wife, Robyn, have an agreement, largely at her insistence. The pact goes back to well before the Celtics forward’s mission was consumed by his recovery from a broken left tibia.

Either his former Utah team had just lost, or he hadn’t played well — especially by a personal set of elevated standards — and he vented that frustration on the way home.

“I’ve always kind of given him after games — like if it’s a bad game and they lose and he’s mad — I give him the car ride home,” Robyn said last week. “And then once we’re home, gotta get over it.“Can’t dwell too much on it, because there’s always another game, another game that same week, so what’s the point of being so mad? You’re going to go to practice the next day, you’re going to watch film, so get over it.

“So I’m not that sympathetic.”

Gordon smiled, nodded and said, “That’s for damn sure.”

Robyn continued.

“Oh yeah, in fact that’s probably a nicer version of what I say. Like we don’t — there’s no reason to dwell, get over it. There’s another game.”

None are bigger than what is approaching. Tuesday night’s nationally televised season opener against Philadelphia is not simply an Eastern Conference semifinals rematch and a fresh steak on the fire of this old, rekindled rivalry.

The night will feature Hayward’s return from a lost season: First, post surgery, with his leg in traction and shooting at the basket from a chair, then getting in the pool and into the monotonous grind of the Anti-Gravity (AlterG) Treadmill. He was generally separated from the team, sequestered in the bleakness of the Celtics’ now former practice facility in Waltham.

But to even get that far, support has to come from within the closest confines. From within the car, the kitchen, the hospital bed, in the company of Robyn and their two young daughters, Bernie and Charlie. The family took part in a much-dissected gender reveal video this summer, when Robyn opened a box of pink balloons to announce she was expecting another girl. Gordon, who later admitted he was hoping for a boy, wandered away from the camera saying, “Daddy is always happy.”

But with all the challenges he faced over the last year, Daddy’s happiness needed some help.

Living in a new world

Robyn is a fighter. When Gordon signed with the Celtics in the summer of 2017, the hurt of Jazz Nation poured out on Twitter, some with a vicious edge. She posted a picture of her and Gordon on Instagram, accompanied by a farewell note that included the following message for the haters: “As for all the mean comments and threats. Don’t forget athletes are humans too. Treat others how you would like to be treated. It would never cross my mind to speak so negatively and so full of hate about oneself or their family.”

Her protective instinct was very much in play last Oct. 17, the night Hayward was flown from Cleveland to Boston and taken by ambulance to New England Baptist Hospital. The morning unfolded with news helicopters circling the hospital and news crews doing standups outside.

“I didn’t realize that there were news copters,” said Gordon, who only learned of the fly-overs this week.

“I did. But you were so preoccupied,” said Robyn, who was talking to Heather Walker, the Celtics’ Senior Director of Public Relations, when someone got a little too close.

A fan made it up to the floor housing the Baptist’s intensive care unit — Hayward’s initial location — and took a seat outside the unit’s locked door. He had brought gifts, including what appeared to be snacks and candy. He was approximately in his late twenties — an impression that made Robyn uneasy. The two women called security and the jilted fan took off, running through the hospital until a guard chased him down.

“Running through the hospital? I did not know this,” said Gordon.

But Robyn now understood how far from Salt Lake City they had come.

“I think his intent was good, but it was super weird,” she said of the fan, “but there were so many people outside. Police were lined up, because so many news people were there. A lot different than what it would have been in Utah.”

When Gordon returned home to Wellesley, a hospital bed was set up in the first-floor family room in front of a TV. The second-floor bedroom was a tough climb, and his beloved gaming room on the third floor seemed like a ski lift away.

The first day wasn’t even finished when Robyn, lugging several small sets of dumbbells, walked into the TV room.

“Like I had just gotten back home. I wasn’t mentally ready to start, I guess,” said Gordon. “I was down the hall throwing a pity party for myself, and she was like, ‘No, no.’ She was just on it, like, ‘Get up. Walk around, you’re supposed to walk around, get up.’ ”

Said Robyn: “They wanted him to do little hand weights with his arms, so I brought a whole bunch of weights up to the hospital bed in our family room, and I was like, ‘OK, let’s do those exercises.’ He was like, ‘I just got home.’ I said I don’t care. That’s what they said, so let’s do it.

“He was probably like, ‘Get away.’ ”

The first two weeks back home considered, it was an accomplishment for Gordon to climb the stairs to his game room. His love of gaming became another form of therapy.

“Mentally, it was just to try and not think about basketball and not think about the situation I was in more than anything,” said Gordon. “Playing video games, I’m talking to my friends while I’m playing and keeping myself occupied. If you’re down, and you’re constantly sitting there or laying in bed, laying in the hospital bed thinking, ‘Why am I not out there, I should be out there,’ replaying different things in your head.”

Breaking bad excuses

The one thing Gordon didn’t do, and still hasn’t, was watch video of the injury — a fracture so horrific that it shocked the rest of the league. He was on the floor during a USA Basketball scrimmage in 2014 when Indiana’s Paul George, during a drive under the basket, broke the tibia and fibula in his right leg.George was one of the first to call Gordon with encouragement and advice, and to share what was behind the success of his own comeback. Teammates and coaches flooded him with attention. Aron Baynes and Daniel Theis, in particular, made routine visits.

“They always made an effort to stop by,” said Robyn. “Aron didn’t live close by, either. Daniel lived close, so we saw them often.”

It wasn’t lost on Gordon that Theis had the same model hospital bed moved into his house following knee surgery last spring.

“Daniel got injured as well, yeah. So then we were in the same boat,” said Gordon. “So I was able to talk to him. We went over and saw him. Definitely when players are around and you talk to them, it definitely makes it better.”

Generally, though, Gordon’s rehabilitation was a solitary time. Once deep winter set in, he rarely saw sunlight on those long days in Waltham at the practice facility.

“It’s dark out when you get there and it’s dark when you leave,” he said. “It gets brutal mentally.”

Gordon’s thoughts and worries admittedly could get a little dark during this time. The family’s home in San Diego was about to play an important role.

“We got the chance to go to San Diego in the middle of the year, and that was really good for me mentally,” said Gordon. “Mental health-wise it was good to get into a new environment. We were there for three weeks, and it gave me a chance to get away from the facility, because in the middle of the winter, even if you’re fully healthy, there’s the dog days of the NBA season, right around January.”

Gordon, in conjunction with The Player’s Tribune and The Athletic, is the focus of a project called The Return. The five-part series details the physical grind of rehabilitation and multiple surgeries, including the removal of a plate from the leg last June. The player about to be raucously welcomed by the crowd on Tuesday night can finally think simply about basketball again.

Slow but steady progress

Gordon played in his first NBA All-Star game the season before his injury. Asked if he’s worried about returning to that version of himself, he said, “I don’t think there’s concern. It’s the timing of it. I would just like to get back to it immediately. It’s frustration, maybe, more than anything.”

His rust has been on full display this month — not enough arc on the jump shot, blown defensive rotations, the slow process of re-establishing chemistry with teammates. He needs games as much as practice time to iron this out. A veteran of slow processes, he’s just started another.

“It’s to the point now where I went through all that, put in so much work, that now I want to be 100 percent,” he said. “It was hard to have that patience of, ‘OK, now I’m playing, but now I have to work my way back to where I was.’ “That’s the hard part. You’re on the court, but you don’t feel like yourself yet. That’s a process you have to get through, and I have nothing in my previous experiences to lean on to where, oh, this is how long it will take, or when I’ll start to feel normal a little bit.”

Post-game car rides will undoubtedly sound familiar. And Robyn will utter some form of those familiar words — “Gotta get over it.”

Asked about her worries, Robyn said, “Just getting his confidence back, because that’s hard to go from not playing for a year and then the expectation is for him to come back and be better than he was at the beginning.

“To become a professional athlete you can’t just snap your fingers. You can’t do that in a year. So to get better I think it will take time. So we have to be patient in not getting down so quick.”