Why Gausman's four-seamer is a strikeout weapon in 2019

Knox Bardeen
April 23, 2019 - 12:31 pm
Kevin Gausman of the Atlanta Braves

Logan Riely/Getty Images


When Kevin Gausman takes the mound Tuesday night in Cincinnati to face the Reds, watch how he strikes batters out.

Contrary to Crash Davis’ mound visit with Nuke LaLoosh in “Bull Durham,” strikeouts are not boring. In fact, they’re fist-pumping, and in the case of Pittsburgh Pirates hurler Chris Archer, sometimes dance-off-the-mound exciting.

His last time out, Gausman tied his career high when he struck out 10 Diamondbacks batters. He’s tallied 22 punchouts in three starts in 2019 and can boast a 10.1 strikeouts per nine innings ratio.

More important, though, than how many Gausman has struck out this season is how he’s fanning these hitters.

As technology around baseball is allowing us to track spin rate and pitch velocity with ease, we’re seeing – and talking about it in the media – just how hard it is for hitters to make that split-second decision on whether or not to swing at a pitch. Is that pitch a strike? Will it stay a strike?

A favorite uses of some of this new tech comes from the Twitter account PitchingNinja, who sometimes overlays two pitches to demonstrate how they look similar... until they aren’t. Here’s a look at a Gausman four-seam fastball paired with a split-finger fastball.

How does a hitter decide which of those to swing at, or which one’s going to stay in the zone? That notion right there may be fueling Gausman’s success this season.

Gausman, through three starts, has changed the frequency he’s throwing certain pitches.

While the average velocity on Gausman’s four-seamer is almost identical to last season and the frequency in which he throws it is fairly similar too, he’s throwing a lot more strikes with it and striking many more batters out with the four-seam fastball.

Kevin Gausman fastball data
Baseball Savant

In terms of the split-finger, Gausman’s strikeout rate is nearly the same to last season, but he’s throwing this pitch way more than in 2018.

Kevin Gausman split-finger data
Baseball Savant

While the split-finger fastball isn’t being used this season any more than is was in 2018 as an out pitch, it’s being used to help his four-seamer be extremely effective as a strikeout offering.

Not only are batters flailing at Gausman’s four-seamer to the tune of a .143 batting average against it (hitters averaged .313 in 2018 against Gausman’s four-seam fastball), 24.2 percent (up from 15.2 percent last season) of the pitches have been missed this season and 28.9 percent of the time (up from 13.6 percent) the four-seamer has been Gausman’s out pitch.

Kevin Gausman 2018 whiff graphic
Baseball Savant

When looking at Gausman’s strikeouts on his four-seam fastball, we see how well he’s doing up in the strike zone.

Kevin Gausman 2019 whiff graphic
Baseball Savant

Where in 2018 Gausman whiff rate came mostly on pitches down in the zone or below the strike zone (read: his split-finger working), this season Gausman is getting swings and misses on his four-seamer up in the zone.

After his last start, Gausman credited Brian McCann for a great job of pitch sequencing and said he had a real good feel for his split-finger. He also spoke about his elevated fastballs.

"I knew early that my fastball up was going to play well," said Gausman. "Just the way it was coming out of my hand early and the way guys were swinging at it."

Go back up and watch that PitchingNinja GIF again. The sequencing Gausman was speaking of basically goes to the way McCann and Gausman were using the combination of his four-seamer and split-finger to get batters out.

Why are Gausman’s fastballs up in the zone working so well this season?

It’s because he’s got “a real good feel” for his split-finger and he’s throwing it more. If that split-finger is working (which is has been) and Gausman’s throwing it more often (which he has been), hitters must adjust to seeing it more often.

That adjustment is opening up the strike zone up top for more success from Gausman’s four-seamer.

Tonight as you watch Gausman pitch, pay close attention to how his four-seamer and split-finger work in conjunction and where his swing-and-miss pitches are located.