Mariners 2021 Free Agent Target: Corey Kluber

I don’t need to tell you who Corey Kluber is. You probably remember him as one of the most dominant starting pitchers in MLB since 2013. Perhaps his winning of the 2014 AL Cy Young over Félix Hernández is a wound that still has yet to heal after six years (although, I remain adamant that Kluber was the rightful recipient). Regardless, I think a strong fit exists between Kluber and the Mariners.

For starters, there exists plenty of downside, and the downside is that Kluber pitches one inning on the year. Why one inning specifically? Because that’s how many innings he tossed for the Texas Rangers in 2020. After compiling 1091.1 innings on his arm from 2014 to 2018 — an average of 219.1 innings per year — Kluber pitched just 35.2 innings in 2019 and one solo inning in 2020. There already existed concern about Kluber’s tanking sinker velocity, and that was before he suffered a second season-ending injury.

Another indicator that Kluber may be done for is that his command waned rather significantly towards the end of 2018.

Here’s Kluber’s seven-game rolling zone percentage:

And, as it follows, his seven-game rolling walk percentage:

Now, there are two ways to interpret these graphs, and they’re not mutually exclusive. The first is that Kluber’s worsening command was forecasting a future injury. He got injured! Twice! The other is that his command is done for good. This is a common side effect of aging. Sometimes it’s trying to reach back for more, sometimes it’s not. Whatever the cause, it’s not yet clear if Kluber’s command will return. With a repertoire that leans heavily on a sinker that gets virtually no swinging-strikes, that’s going to be crucial for Kluber.

I mentioned Félix earlier, and regarding Kluber’s troubles with injury and velocity alike, I don’t feel it’s unfair to say that there are some similarities between the two. They’re both sinker-heavy, and, amazingly, two days apart in age. While it would be tough to watch Kluber have a 2019 Félix-esque year (that hurt to type), I do think he’s set to age more gracefully, assuming he stays healthy. He’s always had stronger command, and he’s retained the ability to draw chases and whiffs with two of his secondaries, while Félix’s changeup sang its swan song in 2017. But, again, assuming full (or even moderate) health may be a stretch given the past two years.

Now that I’ve effectively taken a giant turd on Kluber, I’m free to talk about the reasons why I think the Mariners should sign him — and, to be forthright, I do think they should. The first is that the Rangers declined his option for 2021, and it’s looking likely that he’s going to receive an incentive-laden, one-year contract. We know the Mariners aren’t reluctant to offer players short-term, incentive-laden deals. We just witnessed it with Kendall Graveman!

With a farm system burgeoning with pitching talent — we may literally never stop drafting pitchers! — Kluber would serve as a fantastic stopgap while the likes of Logan Gilbert, Emerson Hancock, and George Kirby tighten it up in the upper minors.

As is, Roster Resource projects the Mariners 2021 starting rotation as Marco Gonzales, Yusei Kikuchi, Justus Sheffield, Justin Dunn, Nick Margevicius, and Ljay Newsome. We know that the Mariners will be moving forward with a six-man rotation, but I’m not convinced that the back half of the rotation should be getting as many looks as they would in this current moment. As for the front end of the rotation, it’s not exactly overloaded with upper echelon talent — and I say that as a Gonzales and Kikuchi truther! Kluber could be the pitcher that props up the ceiling of the Mariners’ rotation.

Ultimately, I think Kluber has plenty left in the tank. He may have been sub-92 mph in his lone start of 2020, but he can get by with a subpar sinker, given the combination of a cutter and curveball that should remain strong pitches, even with diminished velocity. There remains the possibility of a shift towards more secondaries and fewer sinkers, and his four-seam fastball could be used more liberally than it currently is.

The kicker is that there’s little to no downside. Making the presumption that he signs a incentive-laden contract, the Mariners will either get a strong year out of Kluber, or be on the hook for very little cash. While I would sign Kluber to a guaranteed contract worth several, several million dollars, I’m also not a member of the Mariners front office. Boo!

Jerry Dipoto has hinted that these kinds of moves aren’t especially likely, but he’s also one of the bolder general managers in the league, and they haven’t shut the door fully on adding a starter in addition to plenty of bullpen arms. There are more ways that an agreement with Kluber ends well than poorly, and even if it were to end poorly, it can only end so poorly, given that MLB teams are cheap bastards. Kluber could never fill the Félix-sized hole in my heart, but I’d at least take the over on him meeting Justin Dunn’s -0.3 WAR in 2020.