Costello's lack of athleticism doesn't make him a deadly defensive liability at the Summer League level, but he was an extremely foul-prone defender against that relatively low quality of competition. He's a decent interior scorer by Summer League standards, but certainly not a standout.

He'd totally lack the necessary athleticism at the NBA level, and would be undersized to boot. He'd be helpless on defense, both on the perimeter and in the paint, and wouldn't be able to get stops short of fouling. And I think it's safe to say that he wouldn't excel on offense either.

He's a good dude, and a hard worker, but I strongly doubt he'll ever make it in the NBA.