Jonathan Holder is due for a breakout

As bullpens go, you really can't do much better than the collection of arms that the Yankees have currently assembled. They do, however, have one flaw: walks. Last year, the Yankees' relief corps issued 3.76 free passes per nine innings, the 12th-highest mark in baseball. Aside from Tyler Clippard, many of the culprits — Dellin Betances (6.64 BB/9), Aroldis Chapman (3.58), Tommy Kahnle (3.38), David Robertson (3.09), Chasen Shreve (4.96) — figure to see significant playing time for the Yankees in 2018, too.

There was one pitcher in the bullpen who managed to post a BB/9 under two, and he did it while recording above-average run prevention numbers to boot. His name is Jonathan Holder, and I believe he has a lot more to offer than just a low walk rate.

Last November, I covered Holder in our 2017 Yankees Season Review series. In it, I noted that Holder's overall numbers - 3.89 ERA (88 ERA-), 3.62 FIP (79 FIP-), 0.5 WAR in 39.1 innings - were rock solid. His BABIP of .348 had more to do with bad luck than him giving up hard contact, making him a prime candidate for positive regression in 2018. I still stand by these points, but I'm starting to wonder if I undersold him in that piece. Looking at his 2017 numbers and his minor league track record, it seems like Holder has serious strikeout potential that has yet to be tapped into.

Holder recorded a K/9 of 9.15 with the Yankees last year, which is solid but barely above league average (8.97). He posted a swinging strike rate of 12.9%, however, which placed him within the top-third of all MLB relievers with at least 30 innings pitched. All of the pitchers with whom he shared the same swinging strike rate - Tony Sipp, Cam Bedrosian, and Ryan Madson - outpaced him in K/9, with the latter two recording marks above 10.

Holder's minor league numbers provide even more support for his strikeout potential. Over four seasons and 235.2 innings in the minors, Holder owns a K/9 of 9.4. This number, however, is suppressed by his time as a starter in 2014 and 2015. In 2016, when he converted to a relief pitcher full-time, Holder recorded a K/9 of 13.9 across three levels, capping it off with a ridiculous 15.49 mark in 20.1 frames for Scranton/Wilkes-Barre.

Would it be reasonable to expect Holder to recreate that mark in the majors? No. Coupled with his strong swinging strike rate, though, his minor league track record suggests that he could approach and exceed the 10 K/9 threshold.

Admittedly, I'm scouting the stat line here, as I am accustomed to as a blogger with neither athletic ability nor baseball experience beyond the Dobbs Ferry Youth Little League. I’m not alone in liking Holder a bunch, though, as scouts also hold him in high regard. Eric Longenhagen, lead prospect analyst for FanGraphs, graded all of the offerings in his three-pitch repertoire - fastball, cutter, curveball - as above average, highlighting his heater and bender as plus pitches.

If you're still unconvinced, maybe watching Holder do his thing might convince you. In a 2016 post, Jeff Sullivan provided hot GIF evidence of Holder's potential for dominance. If you're looking for more recent proof, here's a beauty of a curve he threw to Rusney Castillo two weeks ago.

I don't know about you, but to me Holder's stuff looks like it's good enough to strike out major league hitters by the dozen.

In short, Holder doesn't walk many batters. He struck out hitters at an above-average rate in 2017, but he has the potential to strike out even more batters. That’s based on a combination of factors, including his his swinging strike rate, his minor league track record, and his stuff. Should he do so, the Yankees would gain a strikeout artist who also excels at limiting free passes — Chad Green lite, if you will. They say managing a bullpen is hard, but if Holder does what I think he can do, then the late innings could be the easiest part of Aaron Boone's gig.