DALLAS -- Dallas Mavericks star forward Cooper Flagg had an MRI Saturday morning that revealed a mild left shoulder sprain, the team announced.

Flagg has been ruled out of Saturday night's home opener against the San Antonio Spurs. He will be reevaluated next week.

Flagg, the reigning Rookie of the Year, suffered the injury when he took a hard foul after a flagrant foul by Indiana Pacers forward Aaron Nesmith on a breakaway late in the second quarter of the Mavericks' road win Friday night. Flagg exited moments later and did not return to the game.

Flagg, 19, was off to a fast start in his second season. He scored 32 points in Wednesday's loss to the Houston Rockets, the highest-scoring performance ever by a teenager in a season opener. He had 14 points, five rebounds, six assists, three steals and a block in 17 minutes before exiting against the Pacers.