BOSTON

Boston Celtics first-round draft choice Robert Williams got a lecture from the team about accountability and said they are moving on from the bad first impression he made by missing a flight and failing to get back in time for summer league practice.

“It’s all on me,” Williams told reporters Tuesday, a day after he missed practice. “So we’re going to push forward and move past that.”

A potential lottery pick who dropped to the Celtics at No. 27 because of questions about his work ethic, the forward out of Texas A&M overslept for a conference call with reporters the morning after the draft, blaming the difference in time zones. He was in Boston last week for an introductory news conference, where he said he knew he would have to work hard to make it in the NBA.

Then he went home to Louisiana and missed his flight back.

Williams, 20, said he was upset with himself for making a bad first impression.

“Missing my flight didn’t help,” he said. “I talked to Coach (Brad) Stevens when I got back and he obviously explained to me about the opportunity. There’s not that many. So, definitely a real wakeup call.”

Williams said he didn’t expect any discipline, except for maybe some extra sprints.

“They discipline you with words, more than you may know,” he said.

Also Tuesday, free agent Brad Wanamaker practiced with the team and was assigned the No. 9 that was last worn by Rajon Rondo.