Jake Odorizzi's pitch mix changes from 2018 to 2019 provided an interesting look at some pitch design ideas. All numbers here will be provided by Baseball Savant and some R investigating I did earlier with my Twitter. His 4-seam, splitter, and curveball all stayed fairly consistent with their usage and horizontal/vertical movement. The real changes are apparent when you see that his cutter movement profile completely changed, its usage went from around 2 percent in 2018 to over 18 percent in 2019, and according to Savant, his slider disappeared.

Odorizzi threw his slider 21 percent of the time in 2018, how does a pitcher just drop such an important pitch from the inventory?

Well, this is probably an example of a pitcher merging two decent pitches into one with a more ideal movement profile that he's more comfortable with. This new pitch, which Savant says is a cutter, features vertical break closer to his 2018 slider than the old cutter and horizontal break that is also closer to the slider, but with velocity that more resembles the cutter. He also threw this new cutter mostly to right-handed hitters (463 of 514 total cutters) and specifically in the "down and away to righties" quadrant, which is typical with slider-type movement.

The vertical movement, at 31.1 inches of drop, drops much more than his rarely-used 2018 cutter which was at 24.5 inches, but less than the old slider which dropped 34 inches on average. Its horizontal movement is really something for a cutter, moving over 5 inches glove-side, much more than the previous cutter at 2 inches but less than the slider at 6.5 inches.

Importantly, this is all occurring as the pitch's average velocity sits at 85.4 mph, while the old slider sat at 83.3. It's still slower than his 4-seam (93 mph) and therefore is probably more of an "offspeed" type cutter, but to get this almost slider-like movement profile as he keeps the velocity near his old cutter is interesting.

What's most important to any athlete with pitch design plans in a competitive sport is that it got results, and gives them a baseline to possibly adjust more if needed. This served as his most frequent pitch other than the 4-seam (18.5% usage) and finished with an xwOBA of .315 (compared to .344 in 2018 with his old slider and .404 in a limited sample with his old cutter). Its put away percentage was higher than the splitter and curve, had the lowest average launch angle of all his pitches (9 degrees), and allowed a lower average exit velo than the 4-seam and curve.

Odorizzi took a slider that had below average vertical movement and moderate horizontal movement, added a few mph, and turned it into a unique cutter with lots of movement. Maybe the idea had something to do with his splitter as both pitches, the slutter and splitter, averaged just over 85 mph and were within an inch of each other on vertical movement. Maybe the splitter and the old slider didn't provide enough differentiation, and having two pitches with similar profiles (other than horizontal movement) makes it tougher for hitters when the cutter goes glove-side 5.5 inches and the splitter goes arm-side 11.5 inches.

Some of these characteristics of a slider also show themselves with usage and location. The pitch plots on Savant and my own look into Odorizzi using R programming show typical slider locations. Glove-side and down. Surprisingly for me, 90 percent of the time it was thrown to a right-handed hitter. I was expecting to see a new cutter mostly helping him against left handed hitters but it appears he likes it as a put away pitch against a righty down and away, and enjoys some ground balls from it as well. Maybe the old slider wasn't effective enough against righties and they wanted something firmer to bring it closer to the split and separate it from his curveball (which averages 75.4 mph).

It certainly caught my eye when I was going through Odorizzi's pitch mix on Twitter, and I'm excited to see how the pitch looks whenever baseball comes back.