San Antonio Spurs coach Gregg Popovich is out indefinitely while recovering from an illness .

San Antonio announced Popovich did not travel with the team on its current road trip at the Los Angeles Clippers on Monday and at Houston on Wednesday. The Spurs host the Portland Trail Blazers on Thursday.

Mitch Johnson will serve as interim coach during Popovich’s absence.

Johnson was informed about 2 1/2 hours before Saturday’s tipoff against the Minnesota Timberwolves that the 75-year-old Popovich was unavailable because of an undisclosed illness.

“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.”

It marked the third time Johnson has served as head coach in Popovich’s absence. Former assistant coaches Tim Duncan and Becky Hammon have also served as Spur’s head coaches because of an illness or medical procedure for Popovich in the past five seasons.

San Antonio defeated Minnesota 113-103 on Saturday.

Popovich is the NBA ’s career leader with 1,390 victories and another 170 postseason wins while winning five NBA titles. He is in his 29th season, all with San Antonio.