San Antonio Spurs small forward Kawhi Leonard will miss Thursday's Game 6 of the Western Conference second-round series versus the host Houston Rockets, coach Gregg Popovich said.Leonard injured his left ankle in Tuesday's Game 5 and hoped to be cleared to play in the possible close-out contest for the Spurs, who lead the series 3-2."Kawhi's out," Popovich told reporters about 90 minutes before tipoff. "He'd rather play."Popovich said Jonathan Simmons will start in place of Leonard.Earlier in the day, Popovich termed Leonard as a game-time decision.Leonard, nursing the left ankle, walked slowly but was able to participate in the team's shootaround on Thursday morning. The 25-year-old told reporters that he would play in Game 6 shortly after the Spurs claimed a 3-2 edge in the series following a 110-107 win on Tuesday."It's not an empirical formula," Popovich told reporters after the shootaround. "You watch, you feel, you talk to the player and you come to a decision. Going to take as much time as possible, see what he feels like, see what I see and make a decision."Leonard sustained the injury when he came down on the foot of Houston's James Harden while turning to run up the court with 5:37 remaining in the third quarter. He played half of the fourth quarter but did not take the court for overtime.Leonard still led the Spurs with 22 points and 15 rebounds. He is averaging 27.8 points, 7.7 rebounds and 4.7 assists during the postseason.The winner of this series will take on the Golden State Warriors in the West finals.