What is a knuckle curveball? First, let me define clearly what this study ... The index finger is not needed at all to throw the pitch, and a handful of pitchers even leave it off the ball entirely.

Would it surprise you if over a quarter of the curveballs delivered by major-league pitchers in 2013 were thrown with a knuckle-curve grip? It certainly surprised me. This was one of the results ...

Want to throw a curveball like Trevor Bauer? This step-by-step breakdown covers grip, spin, and mechanics to help you master his devastating pitch. Watch, learn, and start dropping nasty curves!