By Fangraphs’s version of Wins Above Replacement, Corey Kluber was the tenth most-valuable pitcher in baseball from 2010-19. By ERA+, he’s been 34 percent better than the average pitcher during his career. He won two Cy Youngs and was the ace for a Cleveland team that’s been in playoff contention every year for the past five years. His sinker and curveball are two of the most GIF-worthy pitches in baseball today. He was, simply put, a beast. Writing in the past tense about a pitcher who’s still active feels really weird.
His 2019 was, uh, less than ideal. Kluber never really took off, logging 35 2/3 innings of 5.80 ERA ball before a forearm fracture and oblique strain knocked him out for the remainder of the year. In their eternal cheapness, Cleveland sold low on Kluber and dealt him to Texas for salary relief following the 2019 season. Emmanuel Clase (who throws a 100 MPH cutter) and Delino DeShields (not that one) were included in the deal as well.
Corey Kluber is now something of a reclamation project. How can he bounce back in 2020?
A Walk on the Wild Side
Kluber made seven starts before his injuries got him. That’s a small sample size, but there are plenty of issues to unpack from it. Kluber’s most immediately obvious problem was his control. Like most sinkerballers, Kluber’s always been something of a finesse pitcher. Calling him a sinkerballer almost seems reductive since his other pitches are so good, but the sinker is his primary fastball and arguably his signature pitch. From 2013 (his first full season in the majors) to 2018, he only walked 1.9 batters per nine innings. Fangraphs defines a 1.9 BB/9 as “great,” just for reference.
In 2019, however, his walk-limiting skills evaporated on him. In those 35 2/3 innings, Kluber walked fifteen batters (or 3.8/9, between “poor” and “awful” according to Fangraphs). Again, this is a small sample size, but it’s very tough for a pitcher to get away with that kind of walk rate if he doesn’t strike out every batter who doesn’t walk. He threw 42.7% of his pitches in the strike zone in 2019 (league-average rates sit at 49.9%). If Kluber wants to remain a top-shelf pitcher, he’s gonna have to keep his walks in check.
Fly Balls and Line Drives
Besides his control, Klubot‘s biggest problems in 2019 were his batted-ball outcomes. Sinkerballers thrive on high ground-ball rates, which are good because it’s really tough to hit a home run on the ground. However, hitters around the league have been adjusting their swing paths. The “fly ball revolution” has been driven by hitters (and analytics departments) realizing that getting under a pitch by swinging upwards generates a lot more home runs than swinging on a flat plane. Sinkers move downwards (hence the name), and it’s much easier to get under a pitch that drops like a sinker does. This is one of the main reasons behind sinkers falling out of vogue in recent years in favor of four-seam fastballs.
Kluber’s grounder rate last year was 40 percent, which isn’t bad (an average grounder rate in 2019 was 42.9 percent). Unfortunately, that means that the other 60 percent of his batted-ball outcomes were fly balls and line drives, which is enough for Statcast to classify him as a flyball pitcher. That’s not something a sinkerballer wants to be, and Kluber’s gonna have to figure out how to rein in the fly balls if he wants to return to Cy Young form.
It’s Not All Bad
In fact, it’s not even mostly bad. Sorry about the slightly clickbait-y title. Kluber’s peripheral stats think that his 5.80 ERA in 2019 was very undeserved. His FIP was a much more palatable 4.08, which is a sign that positive regression ought to be coming Kluber’s way in 2020 (for a brief FIP explainer, click here). His BABIP allowed was a way-too-high .370 mark, which basically means that batters were getting some lucky hits against him last season (for a brief BABIP explainer, click here). Batters didn’t hit him any harder than the average pitcher, and his stuff doesn’t look like it’s any less nasty. In short, a lot of Kluber’s advanced metrics think that the punishment he received in 2019 was mostly undeserved.
So, Corey Kluber isn’t really a reclamation project. He’s probably going to be plenty good in 2020, if not quite the world-devouring force of nature he was in the mid-2010s. At least he’ll be getting a shiny new stadium to prove himself in during the summer. With any luck, he’ll have a solid 2020 and set himself up well for a reasonably juicy free-agent contract after the season.
If anyone out there’s interested, most of the data for this article came from this Statcast report on Kluber. It’s a really handy little summary of what he did in 2019.