Taking Out the Trash: Pitchers Who Should Junk Their Worst Pitch

February 22, 2020

Sam Chinitz evaluates starting pitchers who could benefit by using their worst pitch less often. These pitchers could be fantasy baseball sleepers for 2020 with proper adjustments.

Pitch mix changes can make or break a player’s season. That obviously goes for fantasy value as well as real-life. We've already seen how throwing an effective pitch more often could make a huge improvement a la Patrick Corbin. Sometimes pitchers just need to eliminate a pitch to see their numbers improve.

Consider the following: Mitch Keller threw his changeup only 4% of the time last season, and his xwOBA would've been nine points better had he never thrown the pitch. That improvement would've given Keller the 83rd best xwOBA in the league last season -- a 28-spot jump from where he actually ranked.

Below is a list of starting pitchers who stand to benefit significantly by decreasing the usage of their worst pitch. There's no guarantee it will happen, but these SP should be on fantasy owners' watch list to start the season. Pay attention to these starters during spring training, as you may see reports to indicate a change in their pitch mix in 2020.

Martin Perez’s Curveball

Martin Perez’s curveball has been remarkably bad recently. Over the past two seasons, Perez’s curveball has averaged a .462 xwOBA and a 6.87% swinging-strike rate. Additionally, Perez’s curveball was barrelled at a ridiculous 18.5% rate, allowed home runs at a 27% clip, and rarely put hitters away (7% putaway rate). Armed with a strong changeup, a solid sinker, and a developing cutter, there’s really no reason for Perez to throw a pitch that is consistently hit hard and does little to induce strikeouts.

Since Perez's curveball results in worse and more frequent contact than any of his other pitches (the sinker's lower swinging-strike rate is the lone exception), junking his curveball (4.73% usage rate last year) could result in a strikeout rate over 20% and an ERA around 4.60.

Jose Quintana’s Changeup

Quintana bumped his changeup usage up to 11.1% last season, but he should reverse that trend in 2020. Opposing hitters slugged .560 against Quintana’s changeup last season, making it the second consecutive year that the pitch posted the highest slugging percentage of anything in his arsenal.

Ditching the changeup might have a minor negative impact on his strikeout rate, but should help lower Quintana’s barrel rate (7.4% for the changeup) and improve his home run rate (13.28% for the changeup), so a potential small dip in strikeouts should be more than offset by improved contact quality. With three other solid pitches, Quintana should see his ERA fall back around 4.00 if he drops his changeup usage, so fantasy owners should monitor his pitch mix closely in 2020.

Yusei Kikuchi’s Curveball

Kikuchi struggled in his rookie year and his curveball’s poor performance didn’t help. Kikuchi’s curve was abysmal at generating whiffs, posting just a 4.44% swinging-strike rate. Since Kikuchi’s curveball only got hitters to chase the pitch outside of the strike zone at a 16.1% rate, most of the contact Kikuchi allowed was inside of the zone.

Unsurprisingly, Kikuchi’s curveball was hit hard, allowing an 88.9 mph average exit velocity and an 8.2% barrel rate. Kikuchi threw his curveball 15.1% of the time last year, and if he gets that percentage down while increasing his changeup and slider usage, then he could be on his way to being a usable fantasy starter this season.

Mitch Keller’s Changeup

Mitch Keller boasts a pair of strong secondary pitches in his curveball and slider, but the 23-year-old also owns a changeup which has served him poorly. Keller’s changeup was the worst of his offerings as a prospect, and that status hasn’t changed in the major leagues, as the pitch was lit up to the tune of a 1.000 SLG last season. It would be one thing if Keller’s changeup helped him generate strikeouts, but the opposite has been true.

Opposing hitters swing and miss on Keller’s changeup at a mere 14.17% rate -- less than five points below his four-seamer and below the league average for changeups. To make matters worse, Keller rarely throws his changeup in the zone with a 28.6% zone rate, and hitters rarely chase with a low 5% chase rate. Keller only threw his changeup about 4% of the time last year, but he would be better off phasing the pitch out entirely and should be a solid fantasy asset without it.

Drew Pomeranz’s Sinker

Pomeranz threw his sinker just over 6% of the time last season, but his move into the Padres’ bullpen should have Pomeranz ditching the pitch completely in 2020. Despite being his third most-used pitch, Pomeranz’s sinker has been his worst pitch by xwOBA in two of the last three seasons and posted a .425 mark last year. With a league-average 55.2% ground ball rate and 62.7% weak contact rate, sinkers are generally used to induce soft contact and easy groundball outs, but Pomeranz’s sinker does none of that.

Indeed, Pomeranz’s sinker posted a 37% ground ball rate last season, was barrelled at an 11.1% rate, and posted a 37% hard-hit rate. Pomeranz should be able to succeed in the bullpen without his sinker, and he is worth a look from fantasy owners who value holds and long relievers. 

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