Amidst all the prospect hype, Brad Keller has stayed at the top of the Royals rotation

There’s no question that so much of the excitement regarding this Royals squad focuses on the Royals’ young arms of the future. Specifically, those arms include Brady Singer, Kris Bubic, Daniel Lynch, Jackson Kowar, and Asa Lacy, the latter the most recent Royals first round pick in the 2020 MLB Draft. Luckily for Royals fans, Singer and Bubic have made their debuts, and Lynch, Kowar, and Lacy sit in Kansas City, Kansas at T-Bones Stadium waiting anxiously for a possible call up (though it is probably unlikely that Lacy will see the Royals big league roster this year considering he was just drafted and recently added to the Alternate Site).

That being said, Royals fans get the picture: if the Royals are going to have any success in the near future, it will depend on the development of this core of young arms in the rotation. So far, Singer and Bubic have contributed to the Royals rotation to mixed results, but at their age, it is likely that they will take away a lot from this experience and be even better in 2021. As for Lynch and Kowar? It seems likely that one or both will be up before the end of September, especially with Matt Harvey most likely on his way out after a third-straight underwhelming start in a Royals uniform (he only went 1.1 IP and allowed three home runs and five runs against the Indians on Tuesday).

While it is fun to focus on the future of the Royals rotation, it has been easy to forget about one pitcher on the Royals pitching staff who has been one of the most dependable starters since 2018. And that pitcher is none other than Brad Keller, who is coming off another stellar start this year against the Indians on Monday evening.

With all the hype on Singer, Bubic, Lynch, and Kowar, it has been easy for Royals fans to forget about Keller, especially since he missed the first part of the season due to COVID. However, despite going relatively under-the-radar in the beginning of the season, Keller has not only proved that he is still the “ace” of this Royals staff, but he is also demonstrating that he should be an essential part of the Royals future rotation as well, even if he comes with less “prospect pedigree”.

In fact, let’s take a look at what Keller has done this year, and what his performance this season could mean for the Royals rotation in 2021 and beyond.


There’s no question that Keller’s rise to the top of the Royals rotation has been an uncanny road. A Rule 5 Draft Pick by the the Cincinnati Reds in the Winter of 2017, Keller was immediately traded to the Royals for cash considerations. A middling prospect in the Arizona Diamondbacks system after being drafted by them in the 8th round of the 2013 draft, Keller was considered a “good, but not great pitcher” who posted a 4.68 ERA in 26 starts and 130.2 IP with the Jackson Generals of the Double-A Southern League in 2017. When the Royals picked him up from Cincinnati, it was seen that Keller would most likely provide organizational depth, as long as he could get through the 2018 season in Kansas City.

However, Keller proved the naysayers wrong and ended up posting a 3.08 ERA in 140.1 IP over 41 appearances and 20 starts in 2018. The strong rookie performance earned Keller the nod as the Royals “ace” of the rotation in 2019, and though he went through his ups and downs in 2019, he still ended up posting a 4.19 ERA in 165.1 IP and 28 starts.

While he was expected to be the “ace” of the staff again until he was tested positive for COVID, Keller didn’t exactly “thrill” analytical Royals fans in terms of his outlook. Though he has ate innings and been pretty dependable for the Royals the past two years, his advanced metrics don’t exactly impress. Keller’s K/BB 1.83 K/BB ratio over his career is a pretty mediocre metric, and his 6.50 K/9 rate isn’t exactly indicative of a future ace either. Last season, even though Keller lead all starters with 10 or more IP in WAR (2.2), he was third-worst when it came to K/BB ratio (1.74) and -0.16 ERA-FIP difference hinted to more analytically-inclined baseball fans that Keller was perhaps more lucky than good. Yes, Keller is a sinker-ball pitcher who relies on inducing groundballs to get outs (his 1.72 GB/FB ratio was second-best on the team last year of starters with 10 or more IP). That being said, his low BABIP (.283 career BABIP) and HR/9 rates (0.59 over his career) made Royals fans wonder what could happen to Keller’s line should he get a little more “unlucky” in 2020.

Somehow, Keller has elevated beyond these questionable metrics and continues to perform as the “ace” of this Royals staff, even though Danny Duffy is certainly doing his part in terms of competing with Keller for that title (Keller and Duffy are 1-2 in starting pitcher WAR). What Keller doing on the surface is immaculate: 3-1 record, 1.93 ERA, 1.04 WHIP in 28 IP. However, when Royals fans dig deeper into his metrics, Keller’s 2020 performance and future looks even more impressive and promising.

What’s been important to note from Keller is that he has increased his strikeout rate while limiting hard contact at the same time. His strikeout rate increased from 17.2 percent to 20.7 percent from 2019 to 2020, according to Statcast data. That being said, his hard hit rate has decreased from 38.6 percent to 35.1 percent from 2019 to 2020, respectively. Why is this important? It is showing that that Keller is growing as a pitcher when it comes to striking hitters out without sacrificing his ability to induce weak contact. Often times, when pitchers increase in strikeout rate, their hard hit rate increases because they’re trying to pump up their stuff, which leads to more hittable mistakes in the zone. That is not the case for Keller this year though, as he still maintains the essence of who he is (groundball-inducing pitcher) while slightly improving in a category (striking hitters out) that makes him more valuable to this Royals rotation.

One of the more interesting developments with Keller this year is how he’s increasing the utilization of his slider while declining his fastball usage, which has been key to his success this year. In his rookie year, Keller threw his fastball 44.5 percent of the time, according to Statcast data. In 2019, that percentage dropped to 41.8 percent and this year it sits at 37.6 percent. Inversely, Keller only threw his slider 26.2 percent in 2018, but increased it to 31.4 percent last year and 36 percent this year. And that decision has paid off: his put away percentage has increased from 19 percent in 2018 to 20.1 percent to 23.2 percent this season. His slider has become his go-to out pitch, and his increase of this pitch and corresponding decline in his fastball is a big reason why Keller is not only succeeding, but also flummoxing analytically-inclined fans who believe that an elite fastball is key to a starting pitcher’s long-term success.


What’s most amazing about Keller is that he’s only 25-years-old, which is only one-year older than Singer and two-years older than Bubic. However, Keller already has nearly three years of big league experience under his belt, and he will be entering arbitration next year, which means he is set to be a free agent in 2024. Yes, Keller may not generate as much hype as the other five pitching prospects in the Royals system, but Dayton Moore will have a big decision to make on Keller when it comes to his contact.

While Keller may not be as sexy as any of the other five pitching prospects, Moore and the Royals need to commit to Keller financially in the long term. At the very least, the Royals should buy out his arbitration years (three, specifically) with some kind of extension. While Keller’s metrics may not “wow” the Royals’ analytics department, he is exceptional in what he does: he generates ground balls (career 51.7 GB rate), he eats innings (333.2 IP thus far), and he continues to be a competitive pitcher in the rotation who gives the Royals a shot to win in every game he appears in. There was no pitcher hotter in baseball than Shane Bieber for the Indians on Monday, and yet Keller went toe-to-toe with him for six innings. That kind of competitiveness is what the Royals need if they want to be a player again in the American League Central anytime soon.

Keller continues to improve as a pitcher, and admittedly, even I have been surprised how Keller continues to grind, compete and stay in games despite his shaky metrics. I wish his K/BB ratio was better. I wish he generated more strikeouts. I wish his fastball was more elite. But Keller is who he is and he does it well, which is all Royals fans and management can ask out of him.

I’m guessing the Royals didn’t expect Keller to be a top of the rotation starter when they acquired him from the Reds in 2017 shortly after the Rule 5 Draft.

And yet here he is in that position, a rock for this Royals rotation which has improved from the past two seasons.

Safe to say, Royals fans are happy that he not only has arrived to that spot, but also about the possibilities of what he may provide this Royals rotation down the road…

Especially once one or two more of those top pitching prospects join him in the Royals rotation within the next year.

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