Crawford is small and quick. I'd wager Crawford has as much athleticism as Trey ( who is a good athlete). First hand experience tells me the ones who can regularly cover small quick guards (found in the B12) are small quick guards. It is very rare to find a 6'7" guy who can stay in front of a talented small quick guard. Defense is largely about effort. Let's see what we get with Crawford.
BTW, Sinking, I'm not trying to pick an argument just understand how a quick, shifty Crawford is not athletic. Is he weak? No hops?