San Antonio Spurs coach Gregg Popovich suffered a health issue before missing a victory over the Timberwolves on Saturday, according to ESPN’s Shams Charania.

Spurs assistant Mitch Johnson is expected to be the interim head coach for an indefinite period.

It is unclear what the health issue is for the 75-year-old Popovich.

A separate report by the San Antonio Express-News said Popovich is “OK,” but “just needs rest.”

Johnson said he found out he was taking over coaching duties about an hour and a half prior to tipoff.

“He’s not feeling well,” Johnson said. “This has happened before. I think everybody’s just always got to be ready for the next man up. We’ve had it with injuries and sometimes people get sick or don’t feel well or things come up in life. He’s just not feeling well.”

Popovich appeared fined while coaching the Spurs’ win over Utah in Salt Lake City on Thursday night, which was the second game of a back-to-back for San Antonio.

San Antonio is on the road against the Clippers on Monday before they face the Rockets in Houston on Wednesday.

The Spurs said Monday that Popovich did not travel with the team for those games.

The Spurs return home to San Antonio for a matchup with Portland on Thursday.

Johnson, who is the son of former Seattle SuperSonic forward John Johnson, previously filled in for Popovich when the veteran coach was out with an illness in March 2023. The Spurs won that contest against Indiana, 110-99.

In November 2014, Popovich missed a few games due to multiple heart procedures.

Former Spurs coach Larry Brown told the San Antonio Express-News that he believed Popovich was close to retiring at the time.

Popovich, a.k.a. “Pop,” is in his 29th season as head coach of the Spurs and has won five NBA titles with San Antonio.

He was named NBA Coach of the Year in 2003, 2012 and 2014.

Popovich is the NBA’s winningest coach with 1,390 regular season victories and another 170 postseason wins — and is the longest-tenured head coach in American professional sports.