San Antonio Spurs starting guard De'Aaron Fox was ruled out for Game 1 of the Western Conference finals against the Oklahoma City Thunder on Monday night because of a right ankle sprain, dealing a blow to San Antonio in the much-anticipated series.
Fox suffered the injury in Game 4 of the Western Conference semifinals against the Timberwolves when Minnesota guard Ayo Dosunmu landed on Fox's ankle while diving for a loose ball.
Fox finished Game 4 and played in Games 5 and 6 as the Spurs closed out the series.
"It's one of those deals where it's not going away for as long as we're playing, I don't believe," Spurs coach Mitch Johnson said.
Fox said at the Spurs' morning shootaround session Monday that he was "trying to test it out." He was on the court again in Oklahoma City about 90 minutes before tipoff of Game 1, but that second workout obviously didn't go as hoped.
There is optimism that Fox will be back for Game 2, sources told ESPN Andscape's Marc J. Spears.
A nine-year veteran, Fox is averaging 18.8 points, 5.8 assists and 3.5 rebounds in the playoffs after averaging 18.6 points, 6.2 assists and 3.8 rebounds during the regular season.
Fox hadn't missed a game since March 25 and started 72 games during the regular season. The Spurs entered Monday with a 7-3 record without Fox this season.
Spurs center Luke Kornet, who had been listed as questionable because of a left foot injury, is available.
Jalen Williams returned to the Thunder lineup after he missed six games because of a left hamstring strain.
ESPN's Michael C. Wright and The Associated Press contributed to this report.