MIAMI - The initial diagnosis on the severity of Ricky Rubio's sprained left ankle was exactly what Minnesota coach Flip Saunders expected.

It was bad.

How bad won't even be known for another two weeks.

The Timberwolves will be without their point guard indefinitely after an MRI on Saturday confirmed the sprain. Rubio will be re-evaluated later this month, at which time the team will formulate a potential timetable for his return.

"He's in good spirits," Saunders said before Minnesota faced the Miami Heat, not long after Rubio hobbled into the arena on crutches with a boot protecting his ankle. "He feels good. Anyone who knows Ricky, he went through his knee situation a few years ago, he's an extremely hard worker. So he'll get back. If anyone is going to get back as soon as they can, he'd be a guy that would."

With Rubio out, the Timberwolves will rely more on Mo Williams at the point, though Saunders said he's leery of playing the veteran more than 25 minutes a night. Rookie Zach LaVine, who logged a total of 13 minutes in Minnesota's five games entering Saturday, also will become a bigger part of the rotation.

Saunders said he expects there will be a substantial learning curve for LaVine, who started in Saturday's loss at Miami.

"I'm sure my hair will get greyer and I'll lose a few more hairs over the course of things," Saunders said.

Rubio was hurt in the second quarter of Minnesota's loss at Orlando on Friday night. He agreed to a $55 million, four-year extension with the Timberwolves on Oct. 31 and is averaging 9.4 points and a career-best-pace 10 assists per game.

"They have a great insurance player with Mo Williams," Heat coach Erik Spoelstra said. "He's proven himself. He can have big games and he can do it by getting into the paint, much like Rubio, and creating for others. But he also can score and shoot it when he gets going."

Rubio is not expected to accompany the Timberwolves to Mexico City for their game on Wednesday against Houston.

"It's going to be tough without him," Minnesota centre Nikola Pekovic said. "But we're going to have to grind, have to fight. Everybody has to step up. There is a chance for so many players."

Minnesota will remain in Miami through Monday, which means Rubio will have a couple extra days to potentially see swelling in the ankle subside before he flies home.

"He can't put any weight on it to get any kind of weight-bearing X-ray," Saunders said. "Two weeks, we'll be able to look at it and then we'll know."