DALLAS — Rookie of the Year candidate Victor Wembanyama was a late scratch for Saturday night’s game against the Dallas Mavericks after spraining his right ankle when he stepped on a ball boy during his pregame warmup, according to a San Antonio Spurs spokesman.

The ball boy was standing on the baseline when Wembanyama stepped on his foot after making a driving layup over a Spurs assistant coach, causing the 7-foot-4 rookie’s right ankle to roll.

Wembanyama had the ankle retaped, but the Spurs decided to sit him out after further evaluation.

The Mavs won 144-119.

Wembanyama sat out Tuesday’s loss to the Milwaukee Bucks because of soreness in his right ankle. He played 22 minutes in Thursday’s loss to the Chicago Bulls, and coach Gregg Popovich said during his pregame availability that the plan was for Wembanyama to be on a minutes restriction again.

Wembanyama, the No. 1 overall pick, is averaging 18.5 points, 10.7 rebounds and 3.0 blocks. He has played in all but three games this season.