Most nights during the NBA season, Kevin Garnett is the last player to emerge from behind closed doors. To those who cover the team regularly, the hour-plus wait is as familiar a routine as Ray Allen’s pregame shooting ritual.

Occasionally, we can hear his voice booming from the back, talking his non-stop NSFW smack on whoever happens to be behind those doors. Along with the bull sessions, he goes through ice, massages and treatment. “Y’all have no idea what it takes to get this body right,” he said apologetically one winter evening. 

We wait because it’s our job, but mostly we wait because it’s Garnett and throughout the season his postgame media sessions have been as entertaining – and revealing – as his turn-back-the-clock performances on the court. Garnett is perhaps the most private superstar of his era, but this year he has expounded on everything from motivation – I hear you all calling me old – to his dislike of playing center. He’ll throw in occasional tortured analogy that make no real sense but contains kernels of the world according to KG. For a team that has been so consistent and patterned the last four years, the Celtics are going through a major transformation and it’s as if Garnett has been working through the transition in real time.

Some nights we get KG unplugged, like after Game 6 of the Hawks’ series when he let loose on Atlanta owner Michael Gearon, while firing back at unnamed media assailants who may or may not even exist. Other times, he appears tired (or to use one of his words, “Weathered”). His protests notwithstanding, that’s an appropriate stance for a man who has 17 years in this league and more than 50,000 minutes behind his name.    

That was the Garnett who emerged Saturday night after he poured in 29 points, grabbed 11 rebounds, recorded three blocks and who knows how many defensive plays that don’t get tallied in the box score.

“I have no life at this point,” Garnett said. “I go home. I get treatment. Come back in here. Study tape, film. No life at all. This is what it is.”

Someone asked him if he was having fun. “When we win I’m having a lot of fun,” he said. “When we lose, it’s a tough day.” 

Garnett played 38 minutes against Philadelphia in Game 1 and all of the fourth quarter. It’s the third straight game he’s logged that many, which would be unthinkable during the regular season where coach Doc Rivers employed his 5-5-5 plan to great effect. Garnett did the same thing in the first three games of the Atlanta series, with only Game 4’s 20-point blowout serving as a breather.

The last time he played that many in a three-game stretch was in the playoffs last spring against Miami. He was dominant in Game 3, not so much in the final two games of that series. The last time he played 38 minutes in three straight games? You have to go all the way back to the 2008 finals against the Lakers. (Hat tip to WEEI’s stat maven Michael Berger for the research).

Rivers has no choice. When Garnett’s on the court, the Celtics are 16 points better than their opponents per 100 possessions. More importantly, when he’s not in the game, they are 33 points worse.

“He’s great. He really is,” Rivers said. “He’s making it … it’s so hard when he’s off the floor for those 12 minutes or 10 minutes. I mean, you’re in a panic right now. And we have to. Our plus/minus with him off the floor right now is horrendous, so that’s an area we have to improve. But when he’s on the floor he’s doing everything for us.”

An undersold aspect of the Celtics’ late-season surge was the play of Greg Stiemsma who emerged as a solid backup for Garnett and made it much easier to keep the priceless big man fresh. But Stiemsma has struggled in the playoffs and while Ryan Hollins has had his moments, neither player has taken hold of the job.

It would be one thing if Garnett was out there simply because there are no other options, but he’s also been brilliant in the postseason, averaging better than 20 points and 10 rebounds, while shooting over 52 percent from the field and 90 percent at the free throw line. 

“We are gonna ride Kevin all the way until his wheels fall of, and he’s bringing it every night,” Paul Pierce said. “He understands the sense of urgency with this ballclub and he’s giving it everything he’s got out there and he’s looking the 04 MVP.”

Cliché as it is, the sense of urgency can’t be discounted with the Celtics. For five years Garnett, Pierce and Ray Allen have prowled the court together, making up for those wasted years when they were their team’s only option. It’s been a form of basketball nirvana that they found each other when they did and they’re all holding on to each other tightly in what may be their last moments together.

“They understand who we are, where we are,” Rivers said. “It’s not anything we ever talk about but listen, we’re all pretty smart people here and we understand.”

It’s why Pierce is playing 40 minutes a night on a sprained knee and why Allen is fighting through the pain of bone spurs his ankle. Allen wasn’t even sure he could play Saturday morning, but by game time he put it aside and gave the Celtics 32 minutes. “You just deal with it,” Allen said.

Officially, the Celtics say that Garnett has been dealing with a hip flexor injury for most of the season but as with most things KG, his medical info is a closely-guarded secret. One can only assume that he’s dealing with a multitude of bangs, bruises and aches, but he’s not going to stop now. He can’t. The Celtics don’t have much of a chance without him and this may be his last real shot at a title. 

So, we wait. We wait for the next game and the next appearance, marveling at what he’s able to do and eagerly anticipating the choice quotes. “There’s only one Garnett,” he said one night and of all the words he spoke this season, none were more true than those.