Clint Capela’s defensive versatility could allow the Rockets to beat the Warriors. (Troy Taormina/USA Today Sports)

HOUSTON — As reporters file into the victorious Houston locker room a short time after Game 4 of the Western Conference semifinals against the Utah Jazz in Salt Lake City, Rockets assistant coach Roy Rogers is on the phone. He quickly announces he needs to hang up and pulls a reporter aside.

He has something he wants the world to know about Clint Capela, Houston’s 23-year-old Swiss starting center.

“I know everyone else has their bigs, their defensive players,” Rogers says. “But to me — and I can say I’m biased — but the guy is the defensive player of the year. We wouldn’t be where we are as a team defensively without him.

“I think everyone’s kind of surprised to see this going on now. [But] I’m not, because I’ve seen it all year, and he’s just getting more and more confidence.

“He’s barely scratched the surface.”

On that surface, these Rockets are defined by James Harden and Chris Paul on the court and Coach Mike D’Antoni and General Manager Daryl Morey off it.

But if Houston is going to beat the Golden State Warriors — the team it has obsessed over all season — in the Western Conference finals beginning Monday, the difference isn’t going to be any of those four. It will be because Capela has become the rare big man capable of standing up to Golden State’s small-ball lineup, which specializes in terrorizing centers and leaving them anchored to the bench.

Just think about two years ago, when the Oklahoma City Thunder met Golden State at this same stage. Surely, the Thunder’s devastating 1-2 offensive punch of Russell Westbrook and Kevin Durant helped put Golden State in a 3-1 hole. But what truly shook the Warriors were the Thunder’s length and athleticism — most notably, Steven Adams, Oklahoma City’s mountain-sized center, who was quick and agile enough to stay on the floor even when Golden State went small.

When Draymond Green is deployed at center, he can handle virtually any defensive assignment. That, coupled with his ability to operate as a point forward offensively, renders virtually every opposing big man helpless.

Adams, though, proved an exception, and the Warriors had a hard time getting by the Thunder. For Houston to have a chance, Capela needs to have a similar impact.

Capela’s rise over the past two years has been stunning; he went from underutilized backup to Dwight Howard to one of the most versatile centers in the league. Morey has been relentless in his pursuit of Golden State — from trading for Paul to signing P.J. Tucker and Luc Mbah a Moute to employing a switching defense from the first day of training camp — but Capela’s growth truly makes an upset possible.

“I think it definitely surprised me because you just don’t know,” D’Antoni said of Capela’s development. “We all hope, we all work for it. . . . The defense just came from his desire to be a main player in this league, and he’s put a lot of work into it.

“It wasn’t like . . . if you would have asked me two years ago would he be at this level, I would say no, and that would be a surprise. Just his continued growth and just his energy level has gotten high.

“He has some talent, and he’s getting better all the time.”

That has been evident in these playoffs, in which Capela has gone toe-to-toe with traditional big men such as Karl-Anthony Towns and Rudy Gobert.

His impact was summed up in one word by Jazz Coach Quin Snyder after Game 4: “Significant.”

It will be the matchup against the Warriors, though, that will reveal his true value.
Houston is banking on Capela’s ability to switch out onto guards — and still get back to the rim — to allow him to stay on the court against the likes of Stephen Curry, Klay Thompson and Durant.

The 6-foot-10, 240-pound Capella showed flashes of what he can do against Utah — particularly in how he impacted Donovan Mitchell. During the regular season, the star rookie shot 58.7 percent within five feet of the basket and was blocked on 11.5 percent of his attempts. Against the Thunder in the first round, Mitchell shot 60 percent (39 for 65) from the same range and was blocked on 10.8 percent of his attempts.

But against Houston, Mitchell slipped to 54.5 percent (24 for 44). More importantly, he was blocked 10 times — 22.7 percent of the time. It became clear that got into Mitchell’s head, and he began forcing passes that became turnovers.

“We talk about it all the time,” Paul said. “There’s some things that happen throughout the game that don’t show up on the stat sheet. . . . I think Donovan saw Clint, and he tried to pass it, and it’s a steal. I got the steal. It doesn’t show up on the stat sheet [for Capela], so it shows how selfless Clint is.”

It was also a sign of the progress Capela has made over the past two years. He has steadily upped his minutes, from 23.9 per game during the regular season last year to 27.5 this year to 32.0 during the playoffs — including a career-high 37 in that Game 4 win over Utah. His improving physical condition and interest in learning have allowed him to improve significantly since D’Antoni took over and installed him as his starting center two years ago.

“He’s an extremely bright kid, and he studies the game,” Rogers said. “Good or bad, regardless of what other clips I show him, he’s always in tune. He’s just like a sponge.

“Now it’s so fun that we watch film on small guys. Because we’re saying, ‘Clint, you got to know how to guard everybody. You got to know how to guard Donovan Mitchell, [Joe] Ingles, Gobert. You got to know their strengths and weaknesses.’ ”

It’s one thing to switch onto a rookie — even a supremely talented one such as Mitchell — and stop an offensively challenged team (sorry, Jazz). It’s quite another to wind up on Curry, Thompson or Durant and slow the NBA’s most devastating offense.

That’s Capela’s assignment. With Capela on the floor, the frightening pick and roll he has formed with Harden remains a weapon; Green will have to try to body up a far bigger man. With him on the bench, Houston becomes another team trying to play small against a team that has perfected it.

The Rockets believe Capela is up for the task.

“I know how hard he works,” Harden said. “He works his butt off every single day. He’s playing extremely well. His numbers are showing it. What he’s doing on the court is showing it. He deserves it. The encouragement I would give to him is to keep going, keep being who you are and great things will happen.”

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