Inside Warriors’ rotation: Managing minutes, airball benchings and hot hands

Charting who plays when is a meticulous task involving math, physiology and team chemistry. Here’s how head coach Steve Kerr found the right man for that job:

“I looked for the most anal-retentive (assistant) coach I could find,” Kerr explained, laughing.

He found Jama Mahlalela, who joined the Warriors’ staff last season. Mahlalela inherited the PT-charting task from Mike Brown, Kerr’s longtime right-hand man, who left before this season to become head coach of the Sacramento Kings.

Legend has it that nobody can out-anal-retentive (defined as excessively orderly and fussy) Brown, but Mahlalela has risen to the challenge.

“Jama’s incredibly organized, enjoys that kind of work, the structure of what it looks like,” Kerr said. “He’s really good at it. He’s got a good feel for that stuff.”

Quick history on that task: It didn’t used to exist. Back in the day, the best five guys played until they dropped, whereupon the best subs plugged in while the starters were being revived. Wilt Chamberlain, for at least one entire NBA season, didn’t spend a second on the bench. Gradually, coaches began to see long-haul value in strategic resting, or “minutes restriction.”

Now, minutes are carefully doled out to maximize player effectiveness. Stephen Curry, for instance, is charted to play the entire first and third quarters, and the last six minutes of the second and fourth quarters. Those 36 minutes rarely vary.

For Kerr’s first five seasons — each of which ended with the Warriors in the NBA Finals — he didn’t have a pregame chart of assigned minutes. It was more a seat-of-the-pants deal. The key players were older, and the substitution pattern was pretty much set.

Three seasons ago, 2019-20, the Warriors were a mess. Kevin Durant was gone, Curry was injured, there were many young players. That’s when Brown suggested drawing up a chart before every game showing who plays when. Great, said Kerr, whose brain was fried just trying to remember all the new names.

The Warriors finished that season with the NBA’s worst record, but Kerr saw great value in Brown’s charting. It frees him up to coach. General Patton didn’t assign KP duties.

Kerr doesn’t recall his NBA coaches pre-planning the PT, although San Antonio head coach Gregg Popovich did so when he coached the 2021 U.S. Olympic team. With the chart in place, Popovich could tell Kerr and the other assistants, “Don’t wait for me to make the subs, because I’m busy.”

Here’s how it works with the Warriors:

Mahlalela makes up his game chart and emails it to Kerr and assistant Kenny Atkinson by midday before a game. In the staff’s pregame meeting, Kerr and those two assistants confer and make any tweaks.

“You get into a certain groove, like we were the first five games of the last homestand,” Kerr said. “We only had 10 guys available, (the rotation) was pretty obvious, so Jama would send it out, I’d go, ‘Yep, looks good,’ and we didn’t even discuss it.”

Mahlalela carries to the bench his one-page grid showing the substitution pattern. Then stuff happens. One player catches fire, another struggles.

“Sometimes during a timeout, we will discuss whether to make a move,” Kerr said. “One group might be on a run, we’re scheduled to take so-and-so out. We’ll gather during the little early timeout where the coaches huddle, we’ll put our heads together and say, ‘No, let’s stay with this group.’ And then we’ll make our subs once the run is over.”

Do the coaches ever argue over this?

“Argue is the wrong word,” Kerr said. “But debate, yeah, we debate. I ultimately make the decision, but I’ll listen to several voices, and if someone gives me a better reason than the other two guys do, I’ll go with that guy.”

Kerr said it’s rare for him or his assistants take input from players on the PT charting, except on major changes for key players. Last season, Kerr tried shifting Curry’s minutes, then reverted to the old plan. This season, Kerr asked Draymond Green to play more minutes with the second team, to give it leadership and stability. Green readily accepted the challenge.

This season, around the core players, there are a ton of moving parts. One recent game, Andre Iguodala suited up after missing the first 39 games of the season and Andrew Wiggins returned after a 15-game injury absence. The Warriors are trying to give young players valuable experience, but Kerr sometimes shortens their leashes because the team has championship aspirations.

“If I’m going to remove someone from the rotation,” Kerr said, “I always tell them. I never surprise them, and all of a sudden, they’re not playing.”

He said that when he plans to move a player into the rotation for a game or longer, if it’s an older player, Kerr will tell the player in advance, but he won’t always do that with a young player.

“Sometimes with a young guy, you don’t want him to be nervous, so you don’t tell him at all,” Kerr said.

From playing under Chicago head coach Phil Jackson, Kerr learned the value of keeping everyone engaged.

“Phil was the master with that,” Kerr said. “Guy would be sitting there on the bench, hasn’t played in four games, middle of the second quarter, Phil calls the guy’s name, and he’s like, ‘ Me? ’”

Kerr likes to alert players when their PT will rise or fall, so they can adjust their workouts. Again, we’re talking about the new age of player-performance evaluation, when the training staff practically monitors the heart-rate increase and energy output of a player stepping onto the team bus.

In making PT alterations, either pregame or on the fly, players’ feelings are considered.

“I see a lot of college coaches sub guys out immediately if they make a mistake,” Kerr said. “There is power that comes from that, in a good way, if you can motivate guys through playing time. That doesn’t work at the NBA level. If you keep taking guys out for making mistakes, it’s not going to go so well for you.

“For me, anyway, if a guy makes a mistake and I want to take him out, I usually wait a couple of plays, so I’m not embarrassing him, like he’s getting yanked because he just shot an airball. I usually wait a couple of plays and give the player that respect. Sometimes I get angry and want to pull a guy right away and I have to hold my tongue,” he said, laughing.

Still, doling out precious PT is a cold business.

“There’s going to be a (PT) crunch coming up,” Kerr said. “When everybody’s healthy, there’s going to be a crunch, because there are only so many minutes to go around. The starting five, they know their minutes, but once you get to the bench, there’s minutes to be had if you perform well, and minutes to be removed if you don’t.”

It’s Kerr’s job to keep a player’s spirits up while he works his way back onto Mahlalela’s list.

Scott Ostler is a columnist for The San Francisco Chronicle. Email: sostler@sfchronicle.com Twitter: @scottostler