Mavs' Luka Doncic leaves with sprained ankle; X-rays negative

DALLAS -- Mavericks superstar Luka Doncic exited Saturday's game against the Miami Heat in the opening minutes due to a sprained right ankle.

X-rays on the ankle were negative, according to the Mavs, who announced at the end of the first quarter that Doncic would not return to the game.

Doncic injured the ankle early in the game when he stepped on Heat guard Kendrick Nunn's foot while driving to the basket.

After not being able to run back on defense, Doncic left the floor during a timeout with 10:20 remaining in the first quarter. He hobbled to the locker room for further evaluation.

Doncic, the Rookie of the Year last season, has established himself as an early MVP candidate. The 20-year-old…