Stuckey: The Importance of Pitchers With Reverse Splits When Betting on MLB
Photo by Tim Warner via Getty Images. Pictured: House Astros pitcher Lance McCullers
Even some recreational MLB bettors are familiar with how certain players and/or teams fare differently against left- or right-handed pitching, but not as many are familiar with which pitchers have reverse splits. Most left-handed pitchers have more success against left-handed batters and vice versa.
Consequently, it’s one of the driving factors a manager uses when constructing his lineup each night.
However, there are exceptions. Certain pitchers actually have better splits against opposite-handed batters (ex. lefties against righties) as a result of their pitch mix. These pitchers generally throw a high percentage of straight changeups and/or roundhouse curveballs with large breaks. Elite cutters can also factor into the equation. Some may recall switch hitters electing to bat right-handed against Mariano Rivera.
Meanwhile, power pitchers who throw a lot of sliders and fastballs (especially sinkers) generally have the platoon splits you’d expect. Arm angle and release point also play a role. For example, side-armers (remember Justin Masterson) will almost always have extreme platoon splits while a right-handed pitcher like Justin Verlander, who throws directly from the top, can still have just as much success against lefties.
Some of the elite pitchers in baseball with A-plus changeups will have pretty even splits against both sides of the plate. Stephen Strasburg and Lucas Giolito immediately come to mind.
As with most statistics in baseball, you always want to proceed with caution with sample size. You should also recognize that pitchers can change their mix over time as a result of age, a new pitching coach or just the addition of a new pitch they’ve worked into their arsenal.
For example, Zack Greinke has had reverse splits in the second half of his career after altering his pitch mix. In 2009, he threw 60% fastballs and 6% changeups. A decade later, those numbers in 2019 were 46.5% and 22%, respectively.
For your reference, here’s a list of 12 current starters with substantial career reverse splits that fit my minimum inning requirements and have a logical pitching profile for this list:
Walker Buehler hasn’t been in the bigs for that long but he actually has semi-reverse splits for what it’s worth. That said, I don’t necessarily project him having glaring reverse splits moving forward, rather closer to even against both.
Only four southpaws made the cut for this exercise but Julio Urias has very extreme reverse splits in his young career so far that are worth keeping an eye on. Clayton Kershaw also has had reverse splits the past few seasons, which surprises me since his slider is so devastating against lefties — and he’s throwing it more of late.
Marco Gonzales also fits the profile of someone who may have reverse splits going forward. For his career, he has exactly a .320 wOBA against both lefties and righties.
Keep in mind I’m just talking starters here — relievers obviously fit the mold too. I could write an entire article about David Robertson’s extreme reverse splits, for example. But relievers clearly have a significantly smaller impact on the outcome of a baseball bet.
Currently, teams rarely adjust their lineups differently for pitchers with reverse splits. And switch hitters almost never adjust to bat righty against a righty or lefty against a lefty, except for the rare case when a knuckleballer takes the mound. However, maybe that changes in the near future.
Regardless, don’t just blindly assume a team that mashes against right- or left-handed pitching will have an edge against a pitcher just based on whether they throw left- or right-handed. Whether you’re betting or playing DFS, get familiar with your reverse-split guys.
In case you’re wondering, there are also cases where you’ll see a true reverse-split hitter (remember Dan Uggla?), but it’s extremely rare.