Celtics president of basketball operations Danny Ainge unknowingly tipped the team’s first-round selection of Texas A&M big man Robert Williams when point guard Terry Rozier called him during a live webcast.

Rozier FaceTimed Ainge, who answered at the Celtics’ practice facility and eventually revealed the upcoming pick.

“I got to draft a point guard,” Ainge joked when Rozier, Boston’s postseason starter while Kyrie Irving was injured, first asked about the team’s selection. Pressed for the actual pick, Ainge answered, “It’s going to be Bob Williams, but we’re looking at all the medical stuff.”

“I was obviously joking with Terry about the guard position. I had no idea I was on live, whatever it was,” Ainge said. “I thought he was FaceTiming me. I had no idea. But, anyway, that is sort of funny. We’re excited about Robert, and we felt like he was the best player available, and we think he’s a great fit for our team.”

Both Ainge and Celtics coach Brad Stevens revelled in the fact that Williams, a projected lottery pick, slipped to Boston late in the first round.

“[Williams] was a player that we liked coming into this draft process. He’s a rim protector and rebounder, and a guy who can play above the rim on both ends of the court,” Ainge said. “We don’t have much of that. We have a little bit of that, but not what he can do. So his abilities to protect the rim and rebound and run the floor, and I think, are some of his greatest traits and uses.”

Ainge is always two steps ahead, so maybe this was his plan all along? Doubt it, pretty funny gaffe.