One out of a bundle from scouts as reported by ESPN:

Western Conference scouting director: "He would have been the No. 1 pick in last year's draft. That should give you an indication of what kind of talent he is. Of all the other high school kids who've come into the league in recent years, the thing that separates LeBron is that he's physically ready to play. He's strong. He's a manly 6-8, 225 (pounds).

"Having said that, he's able to get by on his physical ability right now. The question is, what happens when he can't just get by on physical ability alone? The mental side, the emotional side, those are unknowns. In high school, the only thing we're seeing is the physical ability. There were a lot of times in high school where Kobe didn't have to play his hardest and we see the same thing with LeBron. What happens when he has to turn it on? Will he be able to play 82 games in a consistent manner?

"When Kobe had to turn it on, he did. You saw his desire to work hard and get better. He was willing to sacrifice. Those are unknowns with LeBron at his age. But skill-wise? He has the ability to be anything he wants. He has the passing skills to be a great point guard. He can be a two guard who gets his shot off the dribble. He has legit (small forward) size. His shot is the one element of his game that has been red-flagged, but he has been working on that. There's really nothing you can nit-pick."

There are many others questioning his physical capacity in an 82 game season, not just his mental stamina over this stretch.

He has, of course, silenced these critics.
For the most part anyway.