Fans raised their eyebrows when first hearing that high school extraordinaire Zion Williamson, the high-flying, air-defying, power-dunking man-child that took the national circuit by storm, had measured at 6-foot-7 and 285 pounds.

By NBA measures, Williamson would be the second-heaviest player next to L.A. Clippers center Boban Marjanovic, who is 7-foot-3 and weights 290 pounds, according to Jonathan Wasserman of NBADraft.Net.

The high school phenom had been described as a player with an NBA-ready body, but NBA trainers believe Williamson could be in danger of potentially raising questions about his commitment to fitness.

per Bryan Kalbrosky of HoopsHype:

“He’s sort of built like a LeBron James-type. But whether he can be highly effective in the NBA with that body type will come down to his commitment to himself,” said David Nurse, an NBA trainer who specializes in nutrition. “He needs to understand nutrition and every little aspect of taking care of himself. He has a body type that could very easily balloon up.”

Williamson has a beefy body type by default, much like James, Draymond Green, Zach Randolph, and others have managed to keep under control heading into the NBA season.

Perhaps the biggest change he must undergo, now that he's committed to Duke University and will start a more rigorous schedule heading into his first year of college, is an eagle-eyed attention to detail on what he eats, when he eats, and how much he eats.

While Williamson has managed to throw down rim-rattling dunks and get off the floor just fine for many impeccable blocks, the wear-and-tear of a longer basketball season, including more constant practices, could make him prone to hitting the shelf more often than he'd like to.

“Heavy daily cardio or bouts of strict dieting will break his body down over time and make him more injury prone,” an NBA trainer said, keeping his name off the record. “The last thing he wants to do is play all year at a heavier weight and then crash downwards toward the NBA Combine and Summer League. This will set back his first two years, mentally and physically. This is always bad long-term, even though the pictures are pretty at the Combine.”

The constant running will eventually lank him out overtime, but if Williamson was to play at this weight, it would prove too taxing on his body to keep up with a league that has gotten more athletic and explosive over time.

Gone are the days of a 325-pound Shaquille O'Neal and other oversized centers like Greg Ostertag and Robert “Tractor” Traylor — Williamson will be forced to adapt and survive if he hopes to ensure that his NBA dream is more than just a dream, but a long-lived reality.