Mark Williams is leaving Duke for the NBA draft after two seasons in Durham, he announced via Twitter.

Williams is expected to be a first-round pick after becoming a defensive stalwart at center for the Blue Devils.

Williams had a strong finish to his freshman season – 16.7 points and 7.8 rebounds per game in Duke’s last six games – and carried that into a strong sophomore season.

The 7-foot, 242-pounder had 11.2 points and 7.4 rebounds per game this past season, along with 2.8 blocks per game. He was named the ACC’s defensive player of the year and was a third-team All-ACC selection.

Williams’ lateral quickness allowed him to have a defensive impact beyond that of a rim protector this season, as Duke switched 1-through-5 on ball screen coverages.

"Mark was a joy to coach," said coach Mike Krzyzewski, who retired following the season. "This is such a special moment for him and his incredible family, and we will miss having the Williamses in our program. ... He is gifted at both ends of the floor and is driven to get even better every day."

The Virginia Beach, Va., native came to Duke as the No. 31 player in the Class of 2020. His departure means guard Jeremy Roach is the only player left from Duke’s six-player class – Jaemyn Brakefield and Henry Coleman III transferred after one season, and Jalen Johnson and D.J. Steward both entered the NBA draft.