OKLAHOMA CITY — The San Antonio Spurs are adjusting to life without Manu Ginobili for the playoffs.

The Spurs got a dose of false hope when he made a brief late-season return from an ankle injury. But San Antonio got the bad news Monday that Ginobili will miss the rest of the season after tests showed a stress fracture in the ankle.

Now, coach Gregg Popovich says the Spurs must adjust their roles again and stay positive heading into the playoffs.

"I look at it as a challenge right now for our team. It's about attitude," Popovich said Tuesday after San Antonio's shootaround before a game at Oklahoma City. "We can do the best possible job we can of continuing to believe in each other and put out the effort that's required to win basketball games or we can feel sorry for ourselves and say, 'Well, gosh, without Manu it's going to be really difficult to reach our goals.'

"That's not how the team is built, I don't think, character-wise."

Ginobili had been averaging 15.5 points and 3.6 assists in 44 games this season, and his 3-point accuracy was down from 40 percent to 33 percent this season. He had two long absences because of the injury. San Antonio is 32-12 with him and 17-15 without him this season.

"It is a little bit of a shock because we thought we had him back and we changed the team around pretty significantly to accommodate that, as far as rotations and people playing, that kind of thing," Popovich said. "Now we'll have to redefine it again and retool it again, but they'll give their best effort, without any doubt."

Ginobili had missed 19 games after the All-Star break to let his stress reaction heal in his right leg, but was sidelined again in his sixth game back — a 101-81 loss to Cleveland on Sunday. A day later, the team learned that the Argentine guard would miss the final six games of the regular season and the playoffs after the injury developed into a stress fracture.

Popovich said the Spurs had tried to be careful and delayed Ginobili's return even after he had been cleared to play, allowing more time to heal the ankle bone. Popovich said Ginobili hadn't had any pain in his first five games back.

"We proceeded under the impression that it was healed. Not getting better — that he was ready to go," Popovich said. "At the time it wasn't a stress fracture, it was a stress reaction, and all the indications, all the films, all the things that the medical people do came out positive with regrowth."

Popovich said Roger Mason Jr. would again take over Ginobili's starting role beginning with Tuesday night's game at Oklahoma City.

"He's a superstar player, and I don't think it's on any one of us to try to go out there and individually do what he does," Mason said. "I think collectively, everybody's just got to raise their game up and it means we have to defend a little bit better, we have to rebound that much better. We have to do everything else better."

The Spurs have already clinched a playoff berth, but have slipped from second to third in the Western Conference and have only a half-game lead on Houston in the Southwest Division. Portland and New Orleans are within two games of San Antonio and trying to get a top-four seed for home-court advantage in the first round of the playoffs.

"We look at it as a challenge and take it on, and whatever happens from there happens," Popovich said. "There's really no other choice."