He watches over them like a father whose children have scattered to various corners of the country, no longer in his charge yet still firmly implanted in his psyche.
"I was watching the Nets the other night and Kevin [Garnett] collided with someone and fell,'' Doc Rivers reported. "My heart kind of skipped a beat. I was thinking, 'Oh no. Is he hurt?' Before, I'd be yelling at him to get up.''
Garnett and Paul Pierce are toiling in Brooklyn for a hugely disappointing Nets team that has been underwhelming under new coach Jason Kidd.
The Celtics will face them on the road Tuesday, and then will return to TD Garden on Wednesday, where Rivers and his Los Angeles Clippers will be waiting.
It's nostalgia week for Boston Celtics fans, yet the reunion with Pierce and KG is likely to be underwhelming. Pierce might still be sidelined with a broken hand, while Garnett is submitting startling career lows in just about every category, including 6.4 points a game and 36 percent shooting.
"My heart breaks for them,'' Rivers said. "It's not what was supposed to happen. It's just so strange. It's amazing how much I watch them.
"I just wanted them to do well. That's all. When I watch them now it's like I'm rooting for [daughter] Callie or [sons] Jeremiah and Austin.''
The Nets are not the only team the coach of the Clippers monitors with regularity. Although he will play the Celtics only twice a year, when Rivers sees footage of former team he can't help but stop, rewind and watch.
In many ways, what he sees is close to unrecognizable: new coaches, new players, new sets, new expectations.
Boston is where he established his coaching credibility and won a championship. It's also where he left after nine seasons under murky circumstances.
When it became clear the Celtics were shifting into rebuilding mode, Rivers balked at being part of the group that sent Paul Pierce and KG packing, and conceded he wasn't mentally committed to a sustained stretch of losing. Celtics president of basketball operations Danny Ainge, who inked Rivers to a five-year extension with rebuilding in mind, was initially surprised, then irritated, by his friend's stance and took the unusual step of sending Rivers a certified letter informing him the organization expected him to honor his contract.
Rivers said he would, but over time it became clear to Ainge that it made no sense to pay a reluctant coach $7 million a season to oversee a team that had no chance of contending. He granted the Clippers permission to talk with Rivers, who ended up taking a job that gave him a contending roster and more weight in personnel decisions.
Rivers knows it wasn't a clean break. He also knows he jeopardized (perhaps even squandered) what was previously a nearly unanimous reservoir of good will in Boston.
"It didn't end the right way, but does it ever?" Rivers said. "I'm not sure anything ever does. Danny and I have had many talks about what happened. We agree on some stuff and we don't agree on other stuff.
"When I won my 600th game the other night, Danny was one of the first guys to text me. It's funny, I laughed when I saw it because I was about to text him. He saw something in me. That will never be forgotten.''
The past few days Rivers has considered his return to Boston, and he recognizes his biggest challenge will be to stay focused on the team he represents now, not the one he left behind.
"I came back a couple of times in the summer, but this will be different,'' Rivers said. "I'm way too emotional. I will have to figure out a way to control that.''
He does not know Celtics coach Brad Stevens, but appreciates what he's accomplished in this young season. Rivers has kept in touch with Jeff Green and receives intermittent text messages from Rajon Rondo, Boston's mercurial point guard with whom the coach often clashed. Rivers said their relationship today is probably as "strong as it's ever been.''
"I keep up with some of the guys,'' Rivers said. "It's been so great to watch Brandon Bass, who came in not really known as a defender, and now is thriving in that role. And I love watching Avery [Bradley] grow. I still say he's 1 or 2 on the list of the best in terms of pressuring the ball. Jeff Green will always be someone I admire, for everything he went through.
"There's not as many guys there anymore. Each year, it's less and less. Things change, and people move on, but I still have a strong emotional attachment there.
"It was the longest place I've been in my pro career, either as a player or a coach.''
His Clippers team is still learning how to play defense with consistency. He believes Blake Griffin will exhibit shooting range, but "it's a work in progress.'' His team is incomplete without two injured players, forward Matt Barnes and guard J.J. Redick. The coach said he and Ainge tried to acquire Redick "three or four times" while Rivers was with the Celtics.
"J.J. is so much better than I thought,'' Rivers gushed. "I always liked him, but I didn't realize how competitive he is, how hard he plays. I guess I should have.
"He drives opponents crazy. He's John Havlicek. Well, he's not John Havlicek, but by that I mean he never stops moving. It's exhausting. We laugh as a coaching staff. He's just running around the other side of the floor and you think there's no purpose to it, but then you realize he's doing it to make the other guy chase him. He wears guys out.''
Does Redick remind him of Ray Allen, the third spoke of the Big Three who led the way to Boston's championship in 2008?
"Very similar to him,'' Rivers agreed, "except Ray had the size so he didn't have to run around so much. You look at it, and you've got J.J. and Ray and Reggie Miller and maybe only a handful of other guys in the league that can do what they do.''
Allen was in the news recently for lamenting the fact that KG and Pierce still hadn't forgiven him for bolting to Miami as a free agent last season.
"I get all that kind of news secondhand now out here,'' Rivers said. "I was walking down the street one day and some guy from TMZ jumps out at me and says, 'Ray just said Paul and KG aren't talking to him.' I'm like, 'What?'
"That's L.A. for you. TMZ is everywhere.''
Rivers said it's no secret that the player who makes his Clippers go is point guard Chris Paul, who reminds the coach of Rondo in many ways. The two players have antagonized each other regularly since they came into the league.
"Chris has the better shot, but he has the same gene as Rondo,'' Rivers said. "They're both insanely competitive, and they both have the same thing where they watch every game and can remember everything that happened.
"I was talking with my coaches about one of our games against Miami when we were all with the Celtics a couple of years ago.
"Chris wasn't in the conversation, but we were talking about a play we ran against the Heat, and Chris jumps in with, 'Dwyane Wade never saw it coming. I was laughing so hard watching that. You guys kept faking like Ray [Allen] was coming off when Miami overloaded on the same side, and Wade kept falling for it.'
"Rondo used to do stuff like that all the time, too. I guess that's why I wasn't a very good point guard. I didn't have that kind of recall.''
Rivers believes the Clippers can be contenders, but maintains "we can't get stuck offensively because of our size, and we should never have a defensive drought.''
When he's not breaking down film of his own team, he laments Pierce's injury and frets that KG's limited minutes have affected his rhythm. He's hopeful Bradley can establish himself as a perimeter presence, because he knows how hard the kid has worked to make that happen. He delights in Jared Sullinger's ascension as a key player and wonders how hard it has been for Green to embrace his role as the first option.
"But honestly, they're not the only guys I think about,'' Rivers said. "When people ask me, 'What do you miss about Boston?' I tell them, 'I miss Jeff Twiss [VP of media relations].
"I miss [director of team security] Phil Lynch and [equipment manager] John Connor. I miss the janitors and the guys who put the floor down.
"You don't go somewhere and live there for nine years and do what we did with that team and think it will leave you. It follows you the rest of your life.
"There are a few choice franchises in all of sports where once you're part of it, that's it. You are part of it forever. You can go on, have other jobs, but no matter where Terry Francona goes, he'll always be part of the Red Sox, for the rest of his life.
"The Celtics will never leave me. I will carry that with me the rest of my career.''