Three early metrics that stick out from Royals relievers

It certainly may be tempting for Royals fans to be experiencing a rollercoaster of emotions to start the 2021 season. After looking good in the Rangers series, and splitting the Indians series, the Royals have lost back-to-back games, which included a 6-0 shutout to the Chicago White Sox on Thursday.

For many Royals baseball fans, it is easy to overreact, and forget that this will be a 162-game season in 2021, not a 60-game one like in 2020.

And the Royals bullpen is a prime example of the over-excitement bleeding through among Royals fans.

After the Rangers series, it appeared like the Royals bullpen was in line to carry this pitching staff once again. Not only were Royals fans hoping that the bullpen could duplicate their performance from a year ago (they finished 8th in bullpen ERA in 2020), but many were also making the reference to 2014 and 2015, when the Royals bullpen was one of the best late-inning units in the game (the Royals had the highest reliever WAR in baseball over that two-year span, according to Fangraphs).

Unfortunately, after rough back-to-back outings, it seems like Royals fans have tabled those “just like 2014 and 2015” statements just a bit. Currently, according to Fangraphs, the Royals bullpen ranks 20th in reliever WAR, though xFIP ranks them at 12th, which is a bit more promising. However, despite the mixed overall metrics, the struggles of some key relievers seem to be worrying Royals fans, especially considering that it is not clear yet who the Royals closer should be after a week of play.

Granted, bullpen roles can always be a little contrived, especially in the modern game, where middle relievers are more valued, even if they do not accumulate gaudy save totals (i.e. Devin Williams of Milwaukee and Giovanny Gallegos of St. Louis). In fact, last year, Ian Kennedy was slated to begin the year as the Royals closer, only to lose out to Trevor Rosenthal, who ended up ceding the job to Holland after Rosenthal was traded to San Diego.

Thus, even in a 60-game season last year, the closer’s role changed so much in Kansas City, and yet, it didn’t seem to affect the bullpen overall, as they still ended up being a productive unit by the conclusion of the season.

However, while the closer’s role may be an issue that shouldn’t be overblown by Royals nation, does that mean everything is gravy? Of course not. That being said, there are some individual metrics from Royals relievers that Royals fans should be concerned, as well as ones that should make Royals fans hopeful as well.

Hence, let’s take at three early metrics from Royals relievers which could give Kansas City fans a sense of what the season could look like for those individual relievers, and perhaps the bullpen overall as well in 2021.


Jesse Hahn’s 98.6 MPH exit velocity on batted balls

Hahn’s tenure as a Royals reliever has been an interesting one. In 2019, he didn’t pitch much, and posted a 13.50 ERA and 2.79 WHIP in six appearances and 4.2 IP. Furthermore, his advanced metrics weren’t much better as well. He gave up a hard hit rate of 50 percent, an exit velocity on batted balls of 93.5 MPH, and a xERA of 8.11. Thus, going into 2020, it was debatable whether Hahn was going to last the whole season on the Royals roster, let alone be a contributor of any sort.

That being said, despite a lackluster Kansas City debut, Hahn was beyond surprising in 2020. He posted a 0.52 ERA and 0.69 WHIP in 18 appearances and 17.1 IP. In 2020, he not only increased his K rate from 25.9 percent in 2019 to 29.2 in 2020, but he also decreased his walk rate from 22.2 percent to 12.3 percent from 2019 to 2020, respectively. Suddenly, Hahn went from an afterthought on the Royals pitching staff at the end of 2019 to one of the Royals most crucial and important relievers in the late innings by the conclusion of 2020.

Unfortunately, so far in 2021, Hahn has been closer to his 2019 self than his 2020 one. Take a look at his percentile rankings thus far, courtesy of Baseball Savant.

One of the most interesting metrics from Hahn’s profile is that he ranks in the bottom 1st percentile in regard to exit velocity on batted balls. As of now, his exit velocity on batted balls is 98.6 MPH, which is 13.1 MPH higher than in 2020. Furthermore, it is also 5.1 MPH higher than his lackluster 2019, which is not exactly a comforting sign that Hahn is due for a bounce back after a rough start to the 2021 season.

Furthermore, his poor exit velocity haunts him in a lot of other categories so far this year. His 70 percent hard hit rate ranks in the bottom four percent of the league. His strikeout rate is down 10.4 percent, his whiff rate is down seven percent, and his meatball percentage is up to 11.1 percent, 2.5 percent higher than last year. Overall, Hahn just is not command his pitches, especially his sinker, as well as a season ago.

Here is an example of Cleveland’s Jose Ramirez taking Hahn deep on a sinker that Hahn leaves up way too high in the zone:

Thus, it’s not surprising that Hahn is one of the worst in baseball when it comes to exit velocity when putting these metrics all together.

Should the Royals give up on him? Well, it’s still early, so it will be interesting to see if Hahn will correct this rough start to the year. In 2019, he was a victim of a bad BABIP, as it was .462. Last year, he was overly lucky, as his BABIP was .108, which was going to be unsustainable in 2021. Now? It’s .333, which is pretty much around league average.

Thus, the real Hahn may reveal himself over the next month, once Hahn gets more outings and innings under his belt. It will be interesting to see what kind of pitcher Hahn reveals himself to be by late May or early June…

And if Mike Matheny will continue to give him innings around that time.


Greg Holland’s 36 percent chase rate

Much like Hahn, Holland isn’t off to the greatest start after a strong bounce back in 2020. After posting a 1.91 ERA and six saves in 28 games and 28.1 IP in 2020, Royals fans widely expected that Holland would be the Royals’ closer in 2021, especially after the Royals re-signed him this off-season. Unfortunately, Holland hasn’t seen much work in high leverage roles, as he has only made two appearances, and is posting a 18.00 ERA and 7.00 WHIP in two appearances and one inning of work thus far in 2021.

Therefore, it’s easy for Royals fans to focus on the bad when it comes to Holland, and not surprisingly, there is a lot of bad. However, one silver lining to Holland’s profile has been his 36 percent chase rate, which is 6.4 percent higher than last year, and his highest chase rate in the Statcast era, according to Savant. Here is a glimpse of Holland getting Cesar Hernandez of the Indians to chase a slider in the dirt, which results in a strikeout for Holland:

Holland has mostly struggled with his fastball this year, as his whiff rate has gone from 23.4 percent to 11.1 percent on the pitch from 2020 to 2021, respectively. Furthermore, hitters have posted a wOBA of .820 on the pitch in 2021 in comparison to a .267 wOBA on fastballs a year ago.

However, his chase rate is a promising sign that some positive regression could be on the way, and his lower exit velocity (87.8 MPH) in comparison to 2020 (89.8 MPH) also demonstrates that Holland could turn things around once he garners more innings under his belt in 2021.


Kyle Zimmer’s 5.3 whiff percentage on fastballs

Zimmer has been off to a great start this year, as he is posting a 0.00 ERA and has only allowed one hit in 5.1 IP in relief this season. Last year was a revelation for Zimmer, as he finally stayed healthy and honed his control after years of struggling with command and injury at both the Minor and Major League level.

In 16 appearances and 23 IP in 2020, the former Royals first round pick out of the University of San Francisco posted a 1.57 ERA and 1.04 WHIP, highlighting those two metrics with a strikeout rate of 28.6 percent and walk rate of 11 percent. In comparison, in 2019, his MLB debut, he posted a 17.6 percent K rate and 18.6 rate. Thus, it’s not a surprise that Zimmer posted a 10.80 ERA in 15 appearances and 18.1 IP two seasons ago.

Last year, Zimmer took some off of his fastball, thanks to some changed mechanics. While his fastball averaged 96.4 MPH in 2019, it only generated a whiff rate of 18 percent, a pretty mediocre mark, according to Savant. In 2020, his fastball averaged only 94.1 MPH, but it was a much more effective pitch, as it generated a whiff rate of 28.6 percent, 10.6 percent higher from his rookie season.

In fact, take a look at how he painted the edge last year against the Cubs’ Albert Almora at Kauffman Stadium:

This season, Zimmer has actually seen an uptick in his fastball velocity, as it currently averages 94.6 MPH. Unfortunately, he has seen a sharp decrease in whiff rate. He is only generating a 5.3 percent whiff rate on four-seam fastballs this year, which at the surface level, is a pretty disappointing number. That being said, his wOBA allowed on the fastball is only .154, which is 121 points lower than his wOBA allowed on fastballs in 2020.

Even though Zimmer has not been able to blow hitters away, he has at least been able to hit his spots, and generate easy outs, as evidenced by him inducing the Rangers’ Ronald Guzman to ground out below to Carlos Santana during the Royals’ opening weekend series against Texas:

Zimmer is experiencing success so far with the fastball, despite a lack of swings and misses. Now, will that sustain? Typically, BABIP tends to correct itself over time in such situations, but with increased velocity and better command of the pitch this year, it is also possible that Zimmer could see an uptick in whiffs.

And if he does see that whiff increase on fastballs, it is enticing to think about what Zimmer might be in the Royals bullpen.

Such an uptick could mean a Royals setup or closer’s role in Zimmer’s future by season’s end…

But it’s way too low as of now…and it could also hint a change in Zimmer’s BABIP and fortunes if that whiff rate doesn’t increase over his next few performances.

Photo Credit: Ed Zurga/Getty Images

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