Miami freshman Lonnie Walker, a five-star prospect from the Class of 2017, tore the meniscus in his right knee during practice Tuesday morning and will undergo surgery later this week.

"The timeframe for his return will be determined after the surgery," said Miami coach Jim Larranaga.

Walker, a 6-foot-5 guard, was a McDonald's All-American coming out of high school and thus is one of the most heralded recruits in Miami history. He's projected as a top-15 pick in the 2018 NBA Draft. But whether Walker will be available to start the season is now unclear, if not doubtful. Like Larranaga said, that'll be determined at a later date.

"I promise this will not slow me down," Walker tweeted Tuesday night.

Miami is ranked 11th in the CBS Sports Top 25 (and one).