Call me an optimist but I like to look at defensive "potential" vs. productivity in projecting D ability, particularly for high-volume scorers in college who spend so much energy on that side of the floor.
My expectation is that every rookie, save 5-6 guys every draft, will come into the NBA and generally suck defensively. So long as they have the physical tools to get there and understand if they don't guard they won't play I'm not too worried. He's long, rangy, athletic enough and plays really hard. I'm not too worried.
Guys like Reed Sheppard scare me more. I know what the defensive metrics say but his size, physique, and length are spooky guarding top end NBA guards.