Jason Vargas’ “New” Weapon Against Left-Handed Hitters

Mandatory Credit: Peter G. Aiken-USA TODAY Sports

Like most left-handed pitchers, Jason Vargas has had more success against lefties than against righties. Unlike most left-handed pitchers, that hasn’t always been the case. While his career splits show a 20-point difference in wOBA for lefty and righty bats, as recently as 2013, lefties had a nearly 20-point advantage in wOBA.

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It does make some sense that Vargas would struggle against some left-handed batters. His fastball barely touches 90 MPH, and his best pitch is a changeup, which tends to work best against opposite-side hitters. Vargas’ curveball isn’t a bad pitch, it just hasn’t been able to consistently put away left-handed hitters.

But something changed for Vargas last season. He held lefties to a .296 wOBA, which was his lowest mark since 2010. It may be easy to dismiss that as a product of the Royals’ defense, and I’m sure that had something to do with it, but Vargas allowed a .311 BABIP to left-handed bats, which is above both his season average and his career norms.

He struck out 16% of the lefties he faced, while walking a paltry 3.1%, by far the best peripherals since his 2005 rookie season. We know Vargas missed bats, and we know opponents didn’t do much damage when they did make contact, and the reason for that is in the batted ball data.

Vargas has been a fly ball pitcher throughout his career, and that was the case in 2014. Overall, he allowed a fly ball rate of 38.7%. As you would expect, his ground ball rate was well below the league average, at 38.3%.

Against lefties, Vargas induced grounders on 52.4% of the balls in play. That’s more than 8 points higher than his career average ground ball rate against lefties. When facing same-side hitters in 2014, Vargas turned into a left-handed Tim Hudson, basically. What did he do differently?

While that is well above his norms, Vargas had a 50.3% ground ball rate against lefties in 2012, so I thought it would make sense to look at his pitch mix that year. Against left-handed hitters in 2012, Vargas’ pitch usage looked like this:

Fastball: 42.1%
Sinker: 21.8%
Change: 8.8%
Curve: 8.7%
Cutter: 18.6%

A cutter can act like a hard slider with less movement at times, so it makes sense he would rely on that as his primary breaking ball against lefties. Now let’s look at the usage in 2014.

Fastball: 34.6%
Sinker: 32.8%
Change: 19.0%
Curve: 13.6%

Well. Vargas threw his hard stuff (relatively speaking, of course) about two-thirds of the time, but he went against the traditional theory and threw his changeup one-fifth of the time to same-side hitters. It’s not a new pitch, but that’s a big change in approach.

In the two seasons before 2014, Vargas was only throwing his changeup to lefties 8% of the time. Between 2012 and 2013, Vargas threw a total of 125 changeups to lefties. He threw 138 changeups to lefties in 2014 alone.

We know that changeups can generate ground balls as well as any other pitch, so that certainly explains the grounder rate spike. Vargas also threw more sinkers, again contributing to more worm-burners.

When looking at the pitch outcomes for the changeup, it makes perfect sense that he would rely on that pitch more frequently than before. Between 2010 and 2013, the change had a whiff rate of 13.5%. In 2014, it was 18.1%. Lefties hit .202 with a .351 slugging percentage against it from 2010 to 2013. Last season, they hit .133 with a .267 slugging percentage.

Changeups don’t usually get thrown that often to same-side hitters, but when they get results like that, why worry about anything else?

Vargas has one of the best changeups in baseball, but he hadn’t thrown it much to left-handed hitters. Maybe he was simply abiding by the old ideas of pitching, or maybe he just didn’t feel comfortable with it, but he tended to only throw it against righties.

Last season, though, Vargas busted out his best pitch in just about every situation. He was able to use that pitch to offset his lack of premium velocity and a consistently above average curveball against left-handed hitters. Vargas’ changeup has helped him limit the damage against righties throughout his career, and now, it seems he can use it to limit the damage against batters in both sides of the box.

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