SAN DIEGO – Midway through his first season coaching the Thunder, Billy Donovan finally implemented a substitution pattern outsiders had long suggested for the franchise. He staggered the minutes of Russell Westbrook and Kevin Durant, ensuring that at least one was on the court at all times.

But in doing so, Durant was forced to break an eight-and-a-half year routine. His entire career, Durant typically played the whole first quarter and then took an extended break to start the second – around six minutes – before returning to close out the half.

This new pattern altered that. He began to play in bursts, essentially mapped out, per half, as follows: Six on, three off, six on, three off, six on. It gave him an early taste of what life will likely be like with the Warriors.

Steve Kerr has already said it’s a “pretty good bet that Steph (Curry) and KD will be staggered.” Curry is pretty settled in a routine that, more or less, sees him play the first nine of a half, sit the next six and then return for the final nine. Durant’s new pattern fits over that perfectly. Kerr has used it during the preseason.

“That looks like what we’ll end up doing,” Steve Kerr said. “Get him out early, get him in at the end of the first quarter and then he can anchor that next group.”

This offseason, Mike Brown replaced the departed Luke Walton as the Warriors’ lead assistant. Among his immediate assignments: revamping Golden State’s substitution patterns.

“Mike is better at math than I am,” Kerr explained.

“Probably (true),” Brown said. “The University of San Diego is a little harder to get into than the University of Arizona.”

All of Brown’s former players describe him as incredibly detailed, obsessed with the little things. He’s commonly seen walking around Warriors practices with a Mac Book.

While an assistant in Indiana back in 2003, Brown took an idea from current Mavericks coach Rick Carlisle, who was the Pacers lead man back then. Carlisle had a hand-written sheet, charting out his planned substitutions for every game.

Brown has done the same ever since. This preseason, before each game, he’s met with Kerr. They discuss the broader plan. Who does Kerr want to play? Around how many minutes does he want each guy to get? Which groups does he want to see together? Then Brown crunches the numbers, fills in his sheet and the substitution plan is formed.

“It’s pretty easy and natural for me to get a few ideas and then go start plugging things in,” Brown said.

But this roster provides one of his trickiest tasks. Not only does Kerr want to stagger Durant and Curry, but the tentative plan is to keep at least two of the four main guys (Klay Thompson and Draymond Green being the other two) on the court at almost all times.

Then there’s Kerr’s commitment to Strength in Numbers. When he was a head coach, Brown typically played nine guys. Kerr prefers to go with 10.

“Which is a positive,” Brown said. “…(But) trying to make it flow so guys don’t get disjointed and they feel a rhythm can get tougher the more guys you play in a half.”

Which is where this basketball math equation can sometimes hit a snag. There are humans involved who have preferences and egos and opinions.

Last season, Durant dealt with some frustration after his pattern was changed. Early in the process, he’d regularly plead with Donovan to leave him in the game, especially if he was struggling. “I can’t find a rhythm,” he told Donovan while walking to the bench once. Durant now says he’s adjusted.

“As a competitor, if you’re not playing well, you want to stay in there and play, gain a rhythm,” he said. “But it’s a team game, man, whatever lineups are best for the team, you got to adjust.”

On any given night, other factors may also alter the plan. What if Curry gets in early foul trouble? What if Durant is scorching to start the game? Does Kerr really want to pull him after, let’s say, he’s hit four 3s in the first six minutes?

“Yeah, maybe you don’t stick with it,” Kerr said. “Maybe if he’s hot you ride it out and take Steph out first. The good thing with our guys is nobody ever complains about it.”