Rubby De La Rosa is a box of chocolates in terms of what kind of start you're getting from him every 5th day. The inconsistency he's had over his career has inspired yours truly to create a Wheel of De La Rosa to try to figure out what kind of start he'd have. At one point, the inconsistency got so bad that the consensus on this website was that De La Rosa needed to be permanently moved to the bullpen. For a week, he wound up pitching in the bullpen but rather out of necessity due to the long games the bullpen had to pitch as opposed to a real assignment change. As a player without options, 2016 was make or break for his overall career.
We know how good he can be. He has the best pure stuff in the entire rotation with a fastball that sits 95, a solid change-up, and slider that's really gotten better of late. Sometimes, the problem is between the ears and De La Rosa loses focus and occasionally will not trust his stuff. When going right, he's causing batters to either whiff or pound the ball into the ground where the Diamondbacks superb infield defense gobbles those ground balls up and turns them into outs. It got really ugly his first start of the year where he got massacred by the Cubs lineup in a Dbacks 14-6 loss. That start prompted HOF pitcher Pedro Martinez to send out this tweet:
I think Ruby thinks too much and he overuses his pitches. He doesn't know how great of a stuff he has, so he still doesn't trust it— Pedro Martinez (@45PedroMartinez) April 8, 2016
Now we move on to his start on April 23rd. De La Rosa ran into some early trouble in the front two innings of the game, but cruised all the way through the 7th inning and picking up the win in a Diamondbacks 7-1 victory over the Pittsburgh Pirates. One pitch that stood out to me was his slider and how effective it was. The slider was responsible for 5 of his 6 overall strikeouts in that game and it baffled Starling Marte and Andrew McCutchen. Even though De La Rosa cut through the Pirates lineup like they were made of paper, there wasn't anything to be really impressed with since their lineup was mostly consisted of right-handed batters, who hit .215 against him in 2015. The slider has always been an effective pitch when complemented with his sinker that works inside to righties.
His next start came against the Cardinals, who had Matt Carpenter, Matt Adams, and Brandon Moss in their lineup. Not exactly stacking it up with lefties, but De La Rosa managed to strike out all three of them at least one in his start. The strikeouts came on backup slider, a 4-seam fastball on the inside black, and two sliders in the dirt. Lefties overall are hitting .211/.333/.368, although I do think it's going to get worse with a larger sample size. Perhaps the solution to his problem with left-handed batters can be found from this start. Against left-handed hitters, De La Rosa threw 19 four-seamers, 8 sliders, 4 sinkers, and 3 change-ups. 3 of the 8 sliders generated whiffs, 2 were fouled off, and the only ball in play was a ground ball.
Last year, Beyond the Boxscore wrote a piece that De La Rosa needed to stop using the sinker against left-handed hitters because the ball would run over the middle of the plate and why he was murdered by left-handed hitters. This year and especially in his last two starts, we're seeing less sinkers and change-ups and more four-seamers and sliders. Adding the slider as a weapon to left-handed hitters complements the 4-seamer and change-up very well as lefties can't eliminate one half of the plate. In addition to the change in repertoire, I would also like the Dbacks to use Chris Herrmann as a personal catcher since whatever he's doing, it's working. Maybe he uses Brooks Baseball when coming up with the game plan for the games that De La Rosa pitches in.