Earlier this week, I read this article on Fangraphs/(rotographs section) by Eno Sarris that displayed and discussed PITCHf/x data from Yovani Gallardo's two-seamer, a pitch he's using more heavily than he has in past seasons, and the data suggests it doesn't seem to be an effective pitch for Gallardo. In fact, it may be hurting his performance.
As far as what the two-seamer is supposed to do for a pitcher, and its tendencies, the author provides a summary on the pitch from Harry Pavlidis's pitch classifications
"the sinker* gets more ground balls than the four-seamer (52% to 36%) and fewer whiffs (5.1% to 7%)"
*The two-seam fastball is sometimes classified as a sinker, due to similar movement - you'll see it at Brooks Baseball, for example.
Sarris goes on to say that Gallardo's GB% from use of the FT (two-seamer), at 45%, is actually just a notch above league average, which isn't high enough to net positive returns. Since t...