MILWAUKEE – As Doc Rivers motioned for him to sub out, Kevin Garnett desperately wanted to stay in, begging his Boston Celtics coach that he had enough left in the tank. Perhaps Rivers would have caved to Garnett’s plead in past years, but not this Saturday night and, most of all, not this season.

“That’s never going to happen,” Rivers adamantly told Garnett on the sideline as he walked over to try to state his case with just over seven minutes left in the fourth quarter and the Milwaukee Bucks leading 71-68.

Indeed, Garnett didn’t get his wish. He has played 17 rugged NBA seasons, but there’s been no fluctuation with his drive. Over and over, Garnett has declared this season that there would have been no point in returning on a three-year contract extension if he took each game lightly. And he’ll privately make clear he’s refreshed, stable in the mind to take a beating inside night in and out.

The Celtics’ new plan for Garnett this season, however, goes against all the principles that have kept this proud, mighty veteran going strong at age of 36. They’ve installed a 30-minutes-per-night regimen, with a desire to keep it even lower. Yes, Garnett played 35 minutes on Wednesday against Washington, but that came after four days off and with two days before the next game.

Had Rivers stuck with Garnett at that seven-minute, 13-second mark on the second night of a back-to-back Saturday, Garnett would have eclipsed 32 minutes for the game. Instead, Garnett went to the bench and returned over two minutes later, with 5:05 left in a tie game.

Rivers was still seething in a hallway outside the Celtics’ locker room after a 96-92 win over the Bucks, shaking his head toward the topic of Garnett’s minutes. As difficult as it has been for Garnett to accept the team’s new plan, Rivers is finding it equally as challenging to assure his minutes hover around – or under – 30 minutes in an effort to sustain his energy over a full season. It is testing his discipline, and when he took a glance at the box score and saw Garnett had surpassed the 30-minute mark by 46 seconds on Saturday, Rivers let out a sigh and simply revealed:

“It’s hard to [manage]; you have no idea how hard that is to know you have 30 minutes to play with. It’s hard. And honestly we want to get it under that. Our goal this year is 27 [minutes per game].”

For all the talk around the NBA about Rajon Rondo’s rise to the top of Boston’s hierarchy, here are the Celtics going through the season with a goal to preserve the man who is literally still front and center. Celtics players touted Saturday’s victory, all proud they finally showed glimpses of crispness on both ends. From Jason Terry to Paul Pierce, they called it a “big” win.

Yet this was just an early-November game in front of a Milwaukee crowd that, to its credit, showed in relatively large numbers. How will Rivers be able to keep his eye on Garnett’s minutes and limit them in late-season games where seeding could be on the line? Rivers promises he’ll pay close attention to Garnett all season long, but what if everyone gets wrapped up in emotions one night at the expense of Garnett’s minutes? The challenges, the obstacles are endless, Rivers admits.

Then, Rivers – the big-picture thinker – stated: “But it’s the right thing for the long haul.”

In the end, this was the right approach on Saturday evening, too. The Celtics had been lethargic throughout the first two quarters, lacking continuity, but took control in the second half. They survived a scare in the opening minute of the third quarter when Rondo banged his right knee battling past a Samuel Dalembert screen. Rondo went down immediately, got up briefly and then instantly leaned back down to grasp his leg, but he just nicked it and ended up with 37 minutes on the night.

A week into the season, the Celtics are still experimenting a lot, totally unsure of their backup point guard situation and tweaking their lineups. Terry and Brandon Bass started in the places of Courtney Lee and Jared Sullinger on Saturday. The Celtics don’t know who can consistently cover for Rondo when he’s sitting, though. Terry and Leandro Barbosa are shooting guards in the bodies of point guards, and Rivers is the first to acknowledge both want no part of the responsibilities that come at the one.

Without Garnett on the floor, it is chaos, as Rondo said Friday evening. The very next night, Rivers was just as poignant about Rondo, sending a clear message that someone will need to step up as a ball handler to lead the offense when Rondo rests.

“We’re really struggling when Rondo goes off the floor,” Rivers said. “We don’t have an offense.”

Boston coaches also swear Jeff Green – whose 12 points led the Celtics’ reserves – is still getting his legs under him after missing all of last season. Lee, meanwhile, has lacked aggressiveness and missed all three shot attempts on Saturday, but he played crunch time minutes locking up Brandon Jennings (four points on 1-for-11 shooting). Soon, Green will find his niche on this Celtics' bench, and Lee will reclaim the starting role as Terry heads back to the sixth man role he thrives under.

In every way, the Celtics’ stars closed out this win exactly the way Rivers wanted: Pierce pushing forth seven of his 25 points in a flurry midway through the fourth as the lead went back and forth, Rondo directing the offense with three beautiful assists across the final four minutes, iced by Garnett (18 points, six rebounds) hitting two straight jumpers right in front of the Bucks’ bench in the left corner, and Bass knocking one down from the same spot 35 seconds later. The latter two sequences capped off a 6-0 run to give Boston an 87-82 lead with just under two minutes left, daggers sending the Celtics to 3-3 and sending them to a Monday night tilt in Chicago where they’ve admittedly struggled in recent seasons.

Rivers wants Garnett to attack and create plays going to the rim, and at one point in the second quarter, K.G. missed a jumper from the top of the key that left Rivers falling back in his seat dejectedly. But there’s a mandate that will come with all of Rivers’ demands this season: We’re going to try our hardest every game to ensure Garnett doesn’t surpass 30 minutes. Garnett pleaded his coach to allow him to play the entire fourth frame Saturday – allow him to burst past the team’s new plan – and Rivers gave him a succinct answer even he found tough to hear: That’s never going to happen.