Room for Improvement: Corey Kluber

Corey Kluber is a great example of the Yankees’ predominant offseason strategy this year – marquee names with risk and high upside, but at a bargain.  The Yankees picked up Kluber on a one-year, $11 million deal. His pedigree can’t be overstated: he is a two-time Cy Young Award winner, finished in the top 10 in Cy Young voting in five straight seasons (2014-18), a three-time All-Star, and at his peak was a reliable innings-eater, averaging 218 innings per season during that five-year stretch. He has consistently outpaced his peers, putting up a career 135 ERA+, and was one of the most feared pitchers in the American League throughout much of the last decade.

2o19 and 2020, however, were lost years for Kluber, as he was plagued by injuries and threw only 35.2 and 1 inning(s), respectively. Therefore, I will preface this piece by saying that it’s difficult to pinpoint where, exactly, room for improvement lies in a 35-year-old pitcher who has functionally not pitched in two years, but who was absolutely elite last time he did (the last time Kluber pitched a full season, he went 20-7 with a 2.89 ERA and finished third in Cy Young voting). Obviously, Kluber’s biggest “room for improvement” coming into 2021 can be boiled down to “throw more than one inning this year.” If he can do that, however, the Yankees have reason to believe that 2021 Corey Kluber will still be a productive addition to a question mark-heavy rotation.

Kluber’s pitcher profile reads as one that could easily translate to graceful aging, even as he returns from injury. At his peak, he was never a pitcher who relied heavily on velocity; he leans more on a cutter-sinker-slider trio than a powerful fastball. His fastball velocity tended towards average to below average even in his great seasons, sitting in the 92-93.5 range for the majority of his career for his four-seam and two-seam (MLB average over the course of Kluber’s career is consistently in the mid-93 range). 

While a consistent 93 mile per hour fastball is nothing to sneeze at, it indicates that Kluber is not a guy for whom an age-related decline in power or velocity is necessarily a death sentence.  It is worth noting that Kluber’s velocity in spring training this season seems slightly reduced based on available data from Lucas Apostoleris of Baseball Prospectus (averaging 91.0 mph on his four seamer and 91.5 mph on his two-seamer), but he has maxed out at close to 94 and may find additional power as he warms up.

Regardless of whether he can consistently reach 2014-18 velocity on his fastball, Kluber’s bread and butter has always been his ability to miss bats and locate.  In his prime, his walk rate was notably low; from 2012-2018, Kluber averaged just 1.89 walks per 9 innings vs. the league average of 3.08.  He struck out an average of 9.8 batters per 9 over those years, compared to a league average of 7.95.  This can largely be explained by the fact that Kluber has shown excellent command of the strike zone.  Over a four year period, he put nearly a third of his pitches on the notoriously hard-to-hit low, outside corner against right handed hitters, and lives on the corners against lefties as well.  See below, which aggregates his 2015-2018 pitch locations by zone against right handed and left handed hitters respectively:

There’s no reason to expect that Kluber would not be able to return to his trademark command once he gets his sea legs under him, and doing so would almost certainly spell a headache for the rest of the league.

Finally, despite 2019 and 2020, Kluber does not have a particularly long injury history, and his issues the past few years seem to stem more from freak things (i.e., getting hit a line drive and breaking his arm) rather than consistent structural physical deterioration. It is also worth noting that Kluber trained this offseason with the Yanks’ Eric Cressey before they signed him, which suggests New York is confident in his health. The Yankees should certainly be careful and not overtax him early in the season – after all, even in the best of circumstances it would take a while for him to build up stamina after two seasons off – but there is reason to hope that, because he does not have a history of suffering from prolonged structural injuries, Kluber will at least be able to add some innings bulk to the rotation.

Corey Kluber is currently Schroedinger’s ace – we don’t know whether he is or isn’t who he used to be until we open the box.  He could be the difference between a Yankees romp to a 28th World Series and a disappointing finish.  While his usefulness in 2021 is difficult to predict, there is certainly reason for Yankees fans to hope that he can regain at least some of the magic of his previous seasons and slot in as a more than serviceable second man in the starting rotation. 


Yankees Spring Training News & Notes: March 17, 2021


Yankees Spring Training News & Notes: March 18th, 2021


  1. dasit

    yankees have a good track record of pitchers adjusting to diminished stuff (mussina, cc, tanaka). i wonder if that experience informed the decision to take a chance on kluber i.e. they had a meeting where they asked him how he was planning to adjust his approach? hopefully he’s not a guy (randy johnson) who requires a personal catcher

  2. Mungo

    Kluber’s room for improvement can be summed up in one word: Health.

    And a cat’s meow for use of the term Schrodinger’s ace.

  3. JJ Dools

    I grade this piece of writing an A+ based on the “Schroedinger’s ace”. That’s great stuff! In all seriousness, that also sums up Kluber since, above all else, he’s a massive question mark. How much fun would it be to see this rotation kit on all cylinders while the big bats stay healthy? After a pretty awful last 12 months, that would really brighten my spirits.

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