SAN FRANCISCO — Even though the Warriors pregame show goes live at 5 p.m. in a few minutes, Jim Barnett is nowhere close to ready. He’s in the green room fiddling with his notes and wiping his hands after a greasy preshow snack.

A producer pops his head in and tells Barnett he needs to be on the set.

Barnett glances at his wrist. “It’s only 4:15,” he protests.

But it’s not. His watch stopped 40 minutes ago. Barnett uncoils his 6-foot-4 frame, straightens his tie, scrambles to the Comcast SportsNet Bay Area studio and, for the next hour, delivers the breezy, accessible hoops breakdown he’s been providing for Warriors fans since the days of Joe Barry Carroll.

When the show’s over, Barnett looks at his frozen watch again. It was a funny thing to happen on the night the Warriors had a chance to reach the NBA Finals.

Because for once in his life, Barnett’s timing is impeccable.

When the Warriors play the Cleveland Cavaliers in Game 1 on Thursday, Barnett will be part of the championship stage for the first time in his basketball life. It took him only 49 years.

Until now, a series of absurd circumstances over the past half-century prevented Barnett from closing things out. The feisty guard was a first-round pick by Boston in the heart of the Celtics dynasty. That team won 10 titles in 11 years. The only miss was in 1966-67, Barnett’s lone year on the squad.

He played three consecutive seasons for the Warriors before the New Orleans Jazz plucked him off the roster in the 1974 expansion draft. In 1975, the Warriors won it all.

While with Philadelphia in 1976-77, the team offered to put the ailing Barnett on injured reserve. Barnett, wanting to spend more time with his family, asked to be released so he could retire. That 76ers team went on to win the Eastern Conference championship.

He’s played with the likes of Bill Russell, Julius Erving, Rick Barry, Pete Maravich and Elvin Hayes.

Great stories, yes. Rings, no.

If things went as they were supposed to, it would have happened again. Barnett had already said goodbye. The only Warriors television analyst fans have ever known announced plans to bow out a year ago after a “mutual agreement” arranged for his contract to expire. Barnett told the San Francisco Chronicle: “Nothing lasts forever. I’ve had a good run.”

But the run wasn’t over.

The watch stopped.

A torrent of support on social media helped lure Barnett back for a 30th — and perhaps defining — season. As analyst for CSNBA’s “Warriors NBA Finals Central,” he can complete the story he’s been telling about Steph Curry’s shooting and Klay Thompson’s emergence and Draymond Green’s defense and Steve Kerr’s mastery.

“It was very heartwarming and very nice. It made me feel good that I’ve done my job. That’s all I try to do, is do my job,” Barnett, 70, said of the fans movement that included a #KeepJim hashtag.

“What I liked about it was the diversity of the people. It went through all spectrums of society, and I like that. It was kind of like you’re the ‘everyman’s person,’ and I like that.”

It didn’t hurt that the Warriors failed to land the high-profile replacement they’d imagined (Tom Tolbert and Brent Barry were rumored candidates). But Barnett doesn’t seem to mind being the default guy.

After all, it’s how his broadcast career started. He recounted his basketball odyssey last Monday while watching Game 4 of the Rockets-Warriors series at the CSNBA studios.

Here’s how it started: Barnett was still an active player, with the New York Knicks, when HBO needed an emergency analyst for the Warriors-Phoenix playoff series in 1976. Russell, his old Celtics teammate, was supposed to serve as the color man but had a travel snafu getting to the Bay Area.

Warriors assistant general manager Hal Childs, who had known Barnett years earlier as a loquacious player at the University of Oregon, alerted the network that Barnett lived just a few miles away in Orinda.

“I’m home. I’m up in a tree cutting down a big oak limb — I mean a huge thing — and I got a call,” Barnett recalled. “So they called me, and I went in and did a game on HBO. I’d never done a game in my life.”

Believe it or not, he was quiet.

“Oh, I didn’t talk too much,” he said. “The (producer) kept saying the first game, ‘Jim, you’re saying good things. Go ahead and talk.’ “

Barnett has been gabbing ever since. That taste of broadcasting soon led to more gigs. He did some Cal games, some other Pac-10 games and even a handful of Warriors game for a fledgling company called Golden Gaters Productions during the 1984-85 season.

It was on the Warriors broadcasts that Barnett first started flashing his keys to the NBA kingdom. Before Golden State faced Philadelphia, the no-name company needed an interview for halftime filler. Barnett got them one of the biggest stars on the planet.

“I said, ‘Let’s get Dr. J,’ ” Barnett recalled with a laugh. “I had just finished my career with Philadelphia a few years before. And so I knew Doc. The Sixers were warming up and I said, ‘Oh, I’ll go get him right now.’ The producers were astounded. But I was still part of it then. You want Earl Monroe? No problem.”

Barnett didn’t formally apply for a broadcasting job until the Warriors expanded their TV franchise for the 1986-87 season.

He got the job and made his debut with a recent import from Indiana, a 23-year-old smoothie named Greg Papa. Their partnership flourished. While Papa kept the action moving, Barnett leaned on his 11 seasons as a solid NBA pro to teach viewers the nuances of basketball.

That the Warriors were often lousy for long stretches of Barnett’s career hardly fazed him. Perversely, he enjoyed it. Back in the days when sponsors were sparse, there was no need to clutter the action with logos and taglines.

“We didn’t have promos in between free throws, so you had plenty of time to show a replay,” Barnett said. “You didn’t have to talk fast. You could show how you block someone off the boards. You could show how you catch the ball and how you establish your pivot foot when you face the basket.”

He has his pet phrases. There’s “quite frankly,” his all-occasion intro when he’s about to dive deep. He’s also fond of “long” or “length” when describing elastic-bodied athletes. He’s such a proponent of the fundamental known as the “triple-threat position” that, on this occasion, he grabs an imaginary ball and tries to deke a reporter out of his loafers.

Dead time — rare these days in the age of the Splash Brothers — is a Barnett forte. The guy has stories to tell. When the NBA announced its “50 Greatest Players” in 1996, Barnett quickly deduced that he’d played with or against 34 of them.

There was the time he played for Red Auerbach for the paltry sum of $11,000, with a $500 signing bonus.

“I didn’t make $1,000 a month. Red Auerbach screwed me. He intimidated me and screwed me. But he liked that, OK? And he thinks he invented basketball,” Barnett said.

There was the time he body-checked Chet “The Jet” Walker, a 6-foot-6, 212-pounder, at Chicago Stadium and paid the price.

“He’s coming across half-court and the ball is way over there. I run in front of him — and boom — we both go down! I get up, and he hit me with his fist. BOOM! Knocked me out.”

There was the time he was playing for the San Diego Rockets and trying to earn his playing time against a hotshot rookie named Pat Riley.

“I never talked to him all year because he played my position and he was trying to take my job,” Barnett said. “He was making $25,000 and I’m making $14,000, and he’s the darling out of Kentucky and all that (baloney). I mean, it was dog-eat-dog. We were enemies!”

(And later friends.)

Over the long haul, Barnett proved good enough to carve his niche in the league as a reliable scorer with a penchant for driving to the basket. Nicknamed “Crazy Horse” as a rookie by Celtics teammate John Havlicek, Barnett went on to average 11.7 points over 732 career games.

His career oddities include immortality in Portland, where Barnett’s shot spawned the “Rip City” nickname. That came during a game against the Los Angeles Lakers, when he let one fly from way out there. (“It was a long one that Curry would take,” he says).

When the ball swished through the net, Trail Blazers radio voice Bill Schonley blurted: “Rip City! All right!”

Schonley doesn’t know why he said it, but it stuck. Rip City has become synonymous with Blazers basketball.

“Even the kids know it up there, because they keep it alive,” Barnett said. “Portland’s alternate jerseys last year had ‘Rip City’ on them. That’s kind of cool.”

These days, Barnett is watching the modern Warriors on the verge of writing a legacy of their own. But it wouldn’t happen on this night. The Rockets pulled away for a 128-115 victory in Game 4, leaving Barnett fidgeting on the couch. At one point during a Rockets scoring binge, he wordlessly vanished and returned to say he’d just washed all of the dishes in the staff break room.

Before surrendering for good and gearing up for the postgame show, Barnett reached into his pocket to grab his cellphone. Former Warriors star Tom Meschery recently wrote a poem about this team, and Barnett offered to give a dramatic reading in the green room.

The verse concludes:

They’re watching these new Warriors, seeing

How luck, timing and the stars triangulate

I’m loving it, so sit back and watch Victory

Happen with the flick of Curry’s wrist

With that, Barnett has to go. He’s late for the set.

Contact Daniel Brown at dbrown@mercurynews.com.