“I do think there’s some combination of having the right grip,” the pitching coach said, “with the right grip pressure, with an efficient arm action and slot, with at least a certain threshold of extension that you get–if you combine all those things well, I think you can create a high amount of spin on a pitch.”

To the public (and possibly private) baseball industry, the secrets to achieving a higher spin rate remain a mystery. There are steps being taken to obtain firm specifications though, most notably by Seattle-based Driveline Baseball. What we do know; however, is that a curveball with more spin results in more groundballs and a higher swinging strike percentage.

When batters come into the box against Stewart, they don’t often know what they’re up against. As his curveball gains velocity, he’s noticed batters are having a tougher time squaring it up. In fact, during the Tournament of Stars, seven of his 13 curves went for strikes and the only one hit into play was a weak groundout.

“I’m starting to throw it harder and harder and throw it in the low 80s, so the harder I throw it, the harder it is to pick up in my opinion. And it’s really just come to if they can see it in time,” Stewart said.

When asked whether he thinks there is a most effective grip for producing spin, Stewart could only say that this method suited him and he wouldn’t throw it any other way.

“It’s just whatever feels best for you. In my opinion this feels best for me and I don’t want to change it,” Stewart said.