I know I'm going to take some heat for this, but Gillis appears to pitch a bit like a muscly guy would pitch. Don't get me wrong, because he is clearly muscly, even somewhat like a gorilla. Given that, I think that while his mechanics are appealing and all, he seems to be drawing a bit more on his muscles than a female would be able to do. Maybe that's why female pitchers generally look more loose with their arms than he does. I dunno.