The concept still seems odd to me, promising to select a prospect late in the first round despite not knowing who will remain available at that point during one of the deepest drafts in years. But a source with knowledge of the situation told me today that the Boston Celtics indeed have made a draft promise to Royce White, as first reported by ESPN’s Chad Ford.

The source told me that the Atlanta Hawks also have expressed interest in White, a 6-foot-8 power forward from Iowa State, but are “operating under the assumption” that Boston has every intention of taking him with either the 21st or 22nd pick.

White can fly on the court, but one red flag surrounding his NBA prospects is an intense fear of flying on airplanes, which led to a few long drives with his grandfather during the college season. My source tells me that White has been flying better, and hasn’t had any big problems during his recent travels. Draymond Green, a draft prospect from Michigan State, has flown with White and said he didn’t notice any issues.

For what it’s worth, Sam Amick and Dan Duggan have both reported that Boston has NOT promised White. A source told Duggan the Celtics aren’t in the business of making draft promises. They are also rumored to be moving one or both of their picks, an option that would make sense as Danny Ainge looks to rebuild a roster that currently contains only four players.

White suffers from anxiety disorder and has a past littered with troubling incidents, like pleading guilty to shoplifting charges at the University of Minnesota and later leaving the school amid suspicion that he was involved in a laptop theft on campus.

“I think that some of the decisions I made at Minnesota were probably very costly to my career there. I also think there are a lot of factors that go into the way that what happened at Minnesota was portrayed and what actually happened,” White once said during an interview. He doesn’t come without concerns.

But he’s talented. Quite talented. Potentially, he could become Boris Diaw with an affinity for the weight room and without an excessive love of croissants. Or, maybe White also loves croissants. His Draft Express profile includes that he “appears to be quite out of shape and overweight.” He measured at 10.6 percent body fat at the NBA Combine — probably not ideal for an NBA athlete but, I’m guessing here, also far from Diaw’s.

Whatever the case with his conditioning, White can do a little bit of everything on a basketball court. He’s a power forward with a bruising frame who can handle on the perimeter and led his Iowa State team in every major statistical category — points, rebounds, assists, steals and blocks. He is a bit undersized height-wise for a power forward, but he has a nice 7-foot wingspan and a 260-pound frame that packs a lot of punch. Plus, most power forwards don’t have White’s all-around game.

If he can manage to dispel doubts about his character, White would be a good fit in Boston, where height and girth are needed and rebounding remains a waterfall in the desert for which Doc Rivers has spent years searching. If White is promised, as I’m told, the Celtics could certainly do worse.

Yet I’m still not sure why the Celtics would make a promise at No. 21. A promise limits Ainge’s creativity and would keep the Celtics from selecting somebody else with their pick if a top talent takes an unexpected fall down the draft order.