Cole Hamels’ Cutter, Graphically

Friend of the blog and fellow esports enthusiast Dan Brooks (@BrooksBaseball) has owned and operated the go-to site for Pitch F/X data for quite some time. Over this off-season, he somehow managed to make some significant improvements to his site. There’s even more data and you are able to permute the data to your heart’s content. During the season, Brooks Baseball will be a must-have in your browser’s bookmarks, right next to Baseball Reference, Baseball Prospectus, and FanGraphs.

To get a feel for the usefulness of the data, I wanted to investigate Cole Hamels‘ spike in ground balls from 2010 to 2011, when he induced them at a 45 and 52 percent rate, respectively. On Hamels’ player card, you can see the chart pictured to the right, one of many such charts.

The cluster of red dots are Hamels’ cut fastballs and the cluster of black dots are his four-seam fastballs. The chart shows that his cutter has more concentrated horizontal movement and less “rise”. You can see the difference in the following two animated .gifs.

Four-seam fastball

Cut Fastball

The cut fastball is a pitch Hamels added in 2010, but it took him a while to get a feel for it. Brooks Baseball shows us that Hamels threw the cutter for a ball 39 percent of the time in 2010, but only 33 percent of the time last year. Additionally, the rate at which he induced ground balls with the pitch changed as well, from 41 of 88 in 2010 (47%) to 91 of 147 (62%) in 2011.

Not only did Hamels increase his use of the cutter last season from 14 percent to 21 percent, but he threw it lower and further away from the middle of the plate. These heat maps, courtesy ESPN Stats & Info, show us the location of his cutters to left-handed hitters in 2010 and 2011.

Obviously, as you go lower and further away from the hitter, the likelihood of a ground ball being hit increases and the quality of contact decreases. As a result, Hamels improved his ground ball rate, and his fly ball rate changed in that he doubled the rate at which he induced infield pop-ups (six percent in 2010 to 12 percent last year) and deflated his HR/FB rate by about five percent.

Hamels set a career-low with a 2.79 ERA last season, partially due to a .255 BABIP. Some — not all — of that is explained by the refinement of his cut fastball, particularly against left-handed hitters. His 2.96 xFIP against lefties was his best since 2007. If Hamels can continue to expertly utilize his cut fastball, then he should be able to maintain a lower-than-expected BABIP going forward. Don’t forget, the cutter is not even Hamels’ best pitch — that honor goes to his change-up, arguably the best in baseball. These two pitches make him plenty valuable not just to the Phillies, but to many other teams praying he will be eligible for free agency after the season.