A candid case for Jesse Hahn in the Royals bullpen

Sorry for the long hiatus in writing all. I just completed a move this weekend as I moved from Strawberry Hill in KCK to the Northland (i.e. Clay County Kansas City). The move was bittersweet, as I loved the area and the community of KCK and Wyandotte County (I currently teach at a Catholic school in KCK), but an absolutely terrible landlord eventually prompted me to find a better deal elsewhere (I will write on this in a post down the road). If you are looking to rent in KCK, please contact me first and let me know which landlord you are talking with, as this guy is a snake, and is not fit to manage property or tenants.

Anyways, that’s my venting of that. Let’s focus onto Royals baseball, specifically the bullpen, which probably remains the most interesting story roster-wise as baseball “hopefully” gets closer to resuming play. As we have heard, it seems that rosters will expand to 29 for at least a month when play resumes, and it is likely that the Royals will be intent on using that roster-space to help their bullpen, as their bench looks pretty solid, and there aren’t a lot of Omaha options really worth pursuing for an extra position spot.

I have talked before about Rule 5 pick Stephen Woods benefiting from this roster expansion, as he likely wouldn’t have made the 26-man roster if COVID didn’t suspend Spring Training and consequently, the regular season. However, Hahn is also an interesting candidate to merit one of the extra three roster spots as well. After getting non-tendered this off-season by the Royals, Dayton Moore brought Hahn back on a considerably cheaper deal worth about $600,000 (he would have commanded around $1 million or so if he was tendered a deal, at least if it went to arbitration). While Hahn has only pitched 4.2 innings since the 2017 season ended due to injuries, the 30-year-old former Athletic and Padres pitcher had some shades of success in Oakland and San Diego, and the Royals were hopeful when they acquired and re-signed him this Winter that Hahn would find a niche in the Royals bullpen in 2020.

Unfortunately, Hahn’s tenure as a Royal has been rough to say the least. In 4.2 innings of work last year, Hahn allowed seven earned runs on seven hits, and allowed six walks as well, which produced an ERA of 13.50 and a WHIP of 2.79, egregiously bad metrics even in a small sample size. This Spring Training, the Royals were hoping that Hahn would rebound and stabilize that rough return to pitching to finish 2019 after a near two-year hiatus. Unfortunately, the Spring was more of the same, as Hahn allowed eight hits and seven runs, as well as three walks and only three strikeouts in five innings of work in Cactus League play. This performance produced a 12.60 ERA and 2.20 WHIP, which is not exactly an improvement from his 2019 metrics.

Thus, it seems clear to some Royals fans that Moore and the Royals should cut ties with Hahn and move on. At 30-years-old, and without any Minor League options left, it would be better for the Royals to give a roster spot on the 40-man to someone with a bit more upside (perhaps Brady Singer, who had a good, though not great, Spring). That being said, I think the Royals should give Hahn at least a month in Kansas City, because even though his tenure as a Royal has not been great, he could provide some upside out of the pen that could surprise Royals faithful in 2020, and maybe beyond.


First off, it has not been an easy past three seasons for Hahn. After being traded from Oakland to Kansas City along with Heath Fillmyer for Brandon Moss and Ryan Buchter, it seemed like the Royals were getting a win-win in the deal. Not only were they getting a pitcher who could add some depth to their rotation, but they would be getting rid of Moss, who never quite lived up to his contract in Kansas City. However, during Spring Training of 2018, Hahn started to experience discomfort in his arm, and it was all downhill from there, as surgery and rehab pretty much took all of 2018 and most of 2019, with a 4.2 inning sample being the lone contribution of his Royals tenure thus far.

Hence, Royals fans who were expecting Hahn to be a solid 4th or 5th starter in the Royals rotation for a few years until the young arms came up should be understandably disappointed. Hahn showed flashes in Oakland and San Diego that he could be a groundball-inducing innings eater, as he posted a 3.07 ERA and 7-4 record in 2014 with the Padres in 73.1 innings of work in 2014, and a 3.35 ERA and 6-6 record in 96.2 innings of work with the A’s in 2015. But while injuries have dogged him as a Royal, there were some hints that Hahn was damaged goods of sorts, as he only pitched 46.1 innings in 2016 and 69.2 innings in 2017 with the A’s before being traded to the Royals.

However, the days of Hahn not being a starter anymore is not necessarily a bad thing. A relief role for Hahn could actually benefit not just him in terms of revitalizing his Major League career, but could also solidify a Royals bullpen that could be surprisingly strong in 2020 if the chips fall just right. For those who are skeptical, check out his Statcast data from a year ago, and there seem to be some signs that Hahn may actually be a better fit in the bullpen than rotation going forward.

A couple of things stick out about Hahn from his Statcast data that should give Royals some hope that his numbers could get better over a larger sample, especially as he grows into a relief role in Kansas City (remember, he was solely a starter until last year and transitioning to the bullpen can be a challenge as it requires a change in mindset and pitch repertoire). First, Hahn throws one of the fastest heaters on the team, as his fastball averaged 95.1 MPH last year, according to Fangraphs. That was the fourth fastest on the team, according to Fangraphs, behind only Kyle Zimmer, Josh Staumont, and Jake Diekman, who is no longer on the Royals.

However, what makes his fastball different than Zimmer and Staumont is that it’s more of a sinking fastball and has a lot more movement on it than Zimmer’s and Staumont’s, making it a nastier pitch to hit. In fact, many pitch trackers had a hard time determining what pitches Hahn threw were fastball and which ones were sinkers in 2019. Fangraphs tracked that he threw his four-seam fastball 62.6 percent of the time, while Statcast said that he only threw it 5.6 percent of the time. Inversely, Statcast said he threw his sinker 57 percent of the time, while Fangraphs didn’t account for him throwing a sinker. Thus, while it’s debatable in terms of what Hahn specifically throws, what’s not up for question is that not only does Hahn throw some heat, but he also puts serious movement on it, which puts him at an advantage over other fireballer options in the Royals pen. Take a look at how Hahn gets All-Star third baseman Matt Chapman to strike out looking with his knee-buckling sinker:

The second thing that makes Hahn stick out as a potential option in the Royals bullpen is that he generated whiffs and groundballs at pretty good rates in his small sample size a season ago. Hahn had a whiff percentage of 30.4 in 2019, which was second only to to Scott Barlow, who may be the closer-in-waiting once Ian Kennedy’s contract expires. Furthermore, Hahn had the seventh-best groundball rate of Royals relievers in 2019 as well, so he has the ability to not just be a strikeout pitcher out of the bullpen, but one who could induce the groundballs necessary to generate double plays and get out of jams. And Hahn has always been a groundball-inducing pitcher over his career thanks to his sinking fastball, as his career groundball percentage is 49.7 percent.


The big issue for Hahn going forward is limiting his mistakes, for when he doesn’t hit the spots, hitters have made him pay, especially last year and this past Spring. Hitters’ 14.3 percent barrel and hard hit percentages against Hahn were the highest of any Royals pitcher in 2019, and thus, it’s not surprising that Hahn’s ERA and WHIP numbers were so bad consequently. Of course, that was over a limited sample size, and another promising sign for Hahn was that he had the third-lowest “meatball” percentage (pitches that can be easily hit for power) out of Royals pitchers a year ago, according to Statcast. Thus, he didn’t make a whole lot of mistakes in 2019, it’s just that hitters made him pay (and then some) when he did.

Despite the ugliness of his metrics, Hahn has all the characteristics of a dependable reliever: good fastball velocity, a lot of movement on his pitches, and the ability to cause hitters to hit the ball on the ground more than in the air. Currently, Hahn throws four pitches (sinker, slider, four-seam and changeup), but it would not be surprising to see Hahn focus solely on his sinker and slider in 2020, especially out of the bullpen where he will only throw an inning or two max for each outing. That could help him hone his command a bit more, which could make him not only more effective against hitters, but could also make him a more reliable option out of the pen for manager Mike Matheny.

What kind of role though Hahn settles into though could make or break his tenure in Kansas City in 2020. One interesting option could be to make him an “opener” as he has the kind of high velocity stuff to fit in the role like other “openers” on other clubs who have incorporated the strategy such as Tampa Bay and Oakland. Furthermore, his experience as a starter might make him more comfortable in the “opener” role than out of the pen in the middle or late innings. That being said, even if Matheny uses him in a traditional way, it takes some adjustment for any pitcher to embrace the bullpen role. After all, Kennedy had an 8.10 ERA in 10 innings of work in May of last year before he followed it up with a 0.96 ERA in 9.6 innings of work in June. Thus, with another 15-20 innings out of the pen, it is possible that Hahn could find his groove out of the pen, much like Kennedy before him a season ago.

Of course, the odds are against Hahn. As stated before, he’s on a cheap, one-year deal, and at 30-years-old, he’s not part of the Royals’ plans long-term. But his effective sinker-slider combo could be a valuable asset for the Royals out of the pen, and it’s possible that he could provide some valuable contribution to the staff in Kansas City, while at the same time, helping the club preserve the service time of Singer, who may struggle considering the weird and most likely shortened conditions of the 2020 season.

2020 may be the last hurrah for Hahn in Kansas City, for even if he does succeed, Moore probably won’t pony up the dough to keep a 31-year-old reliever. But Hahn can bring some production to the pen.

He just needs some more innings of work in 2020 to prove it.

2 thoughts on “A candid case for Jesse Hahn in the Royals bullpen

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