The First Half’s Most Improved Pitch

Want to be a better pitcher? Pick one of your pitches and work on it all offseason. Change the grip. Alter the release. It can change your career.

At best, you might find a new pitch that changes everything for you, like the time Clayton Kershaw picked up the ball and tried to throw a slider for the first time. Or you’ll improve an old standard that has faded, as Cole Hamels has done with his curveball this year.

While this sort of improvement happens so often in spring, or in the offseason, the most improved pitch of the first half is actually improving in front of our eyes.

When the Rays traded for 27-year-old starter Nate Karns this past offseason, it was probably for his power curveball, which sat among the curves thrown by Craig Kimbrel, David Robertson, and Kevin Jepsen as the only ones that topped 83 mph while also having six inches of drop.

That sort of velocity, paired with that sort of drop, should make Karns’ curve one of the best in the game. And while it has, even at a slightly reduced velocity this year — his 11% whiff rate is top-20 among curveballs thrown at least 300 times — the real story here is the right-hander’s changeup.

No pitch — thrown at least 150 times by a starter — has improved as much by whiff rate since last year as Nate Karns‘ changeup. He’s added 14.6% points to his whiff rate for that pitch this year when compared to last year.

The Rays must have continued to like Karns’ changeup — even if he only threw 11 of them last year and didn’t record a whiff — because they turned to him first when injuries began to decimate their rotation, and he’s rewarded them with a top-ten strikeout rate for a rookie and what looks like a starter’s profile.

Karns spent spring training trying to improve the pitch, apparently. When you look at his overall numbers, the change still doesn’t have as much drop as your average changeup (about an inch less), but it’s still improving as he throws it more.

Karns has added three inches of fade this year over last year, and as the season has gone on (and he’s used it more), he’s added another inch of drop. Courtesy BrooksBaseball, watch the movement on the changeup improve over the course of this year. See how the line moves closer to four as the season has gone on? That’s important, because it represents average drop for a right-handed changeup.

Average vertical movement on Nate Karns‘ changeup over the course of 2015.

Drop and fade are great for changeups. Over the past month, Karns has shown average drop for the first time, to pair with above-average horizontal movement and below-average velocity gap. It’s impressive given where he started, and it makes sense given what pitchers say about changeups being “feel” pitches that you have to throw for a while to master.

Paired with a plus curveball and average velocity — too bad Karns dropped from the 93 mph he used to average, but he’s still average for a righty — an average change and average command could produce a lasting above-average starter. And when you look at Karn’s change from the beginning of the season (left) to now (right), it’s fair to dream a little further.

It may look like incremental change, but it’s important. If he can improve the change in one half-season, what more could the Rays’ righty do going forward?