If there’s one pitcher on the Royals roster this Spring who has seemingly benefited from the new Royals coaching staff this Spring, it may be Brad Keller, who is entering his last season of team control with the Royals.
In three appearances this season, Keller has been stellar, as he has produced a 3.52 ERA and 1.04 WHIP in 7.2 IP in Cactus League play. What’s been even more impressive has been Keller’s ability to limit walks while maximizing his strikeouts, something he has struggled with over the past two seasons. In his three Spring Training outings this year, he has not just struck out 10 batters, but he has only walked two as well.
To give some context regarding Keller’s improved command and control this spring, he is currently producing a K/BB ratio over 5.00. For his career, Keller has generated a K/BB ratio of 1.84 in 633.2 IP, which is below the typical league average of 2.00.
Safe to say, the former Rule 5 draft pick has seemed to thrive under new manager Matt Quatraro and pitching coach Brian Sweeney so far in Cactus League play.
That said, is this improvement a sign of things to come for Keller and the Royals in 2023? Or is it simply a “Cactus League Success” story for the Royals that will fizzle out come May?
Let’s take a deeper look into Keller’s profile, and if he will not just earn a spot in the Kansas City rotation out of Spring Training, but also have an impact on a Royals pitching staff that ranked 27th in starter ERA in 2022.
Keller’s Pitch Mix in 2022
I had talked about this in my initial post when I introduced Pitcher List’s PLV, but Keller’s PLV and PLA profiles paint an interesting picture, as one can see in the graphic below:

Based on Pitcher List’s PLV metrics, Keller’s slider was an above-average pitch in 2022, which isn’t bad considering it also happened to be his most utilized pitch as well (it had a 36 percent usage rate). However, his other pitches were a lot less effective, which can be seen in the data above as well as the pitch distribution chart below, also via Pitcher List:

His four-seamer, which he threw nearly 35 percent of the time, was his second-best pitch via PLV metrics, with 4.15 PLA and 4.93 PLV marks. On a run-value end, via Baseball Savant, while the four-seamer was worth five runs above average (positive isn’t good), it was 13 runs better than his total in 2021, when it was one of the worst pitches in all of baseball in terms of run value.

Keller threw the four-seamer nearly six percent more in 2022 in comparison to 2021, and he saw a lot of positive gains in a variety of categories.
His wOBA on the pitch decreased by 90 points, his K rate improved by 1.6 percentage points, and his put-away rate improved by 0;9 percent. Therefore, it’s not a surprise that Keller’s four-seamer was an improved pitch for him in 2022, even if it did not help his overall line last season (5.09 ERA in 35 appearances and 139.2 IP).
What’s interesting to note is that Keller actually saw an improvement in four-seam velocity over the course of the season, which can be seen in the chart below, via Baseball Savant.

After averaging under 94 MPH on the four-seamer in April and May, Keller was able to pump his four-seamer to over 95 MPH by the end of the 2022 season. In the last month of play, not only was Keller averaging 95.6 MPH on the four-seamer, but he was also generating a whiff rate of 27.8 percent and holding hitters to a .277 wOBA on the pitch to boot.
Here’s an example of Keller pumping the four-seamer up to 98 MPH up in the strike zone in September against Eloy Jimenez of the White Sox. As expected, Jimenez swings and misses on the pitch, resulting in a strikeout.
On the flip side, Keller’s sinker, which he threw around 23 percent of the time in 2019, was rated as a mediocre pitch on a PLV end (4.56) as well as a run value end (+8). Furthermore, his changeup only produced a 4.21 PLV, which was his worst pitch in 2022 on a PLV end, via Pitcher List.
Granted, the changeup did generate a whiff rate of 20 percent last year, which was his second-best pitch in this category, according to Savant That would make Royals fans believe that it was a decent pitch, especially when compounded with his +1 run value, which was one of his better pitches on a run-value end a year ago. However, it also produced a hard-hit rate of 45.8 percent, which was the second-worst mark in that category of his pitch mix in 2022.
Here’s an example of that changeup not only being hung in the strike zone, but also getting ripped by Twins second baseman Jorge Polanco.
Keller has some solid potential for this upcoming season as a starting pitcher, especially with his primary two pitches (slider and four-seamer) profiling as above-average offerings.
That being said, his struggles with his other two pitches have not only contributed to two lackluster campaigns in 2021 and 2022 but also should make Royals fans skeptical that he could hold onto a rotation spot in Kansas City in 2023 as well.
The Curveball Addition
One of the biggest developments this Spring for Keller has been the addition of a curveball to his pitch repertoire, which was developed this offseason at Driveline Baseball, the pitching development factory led by Kyle Boddy, who was previously a pitching coordinator in the Cincinnati Reds organization.
The decision for Keller to work at Driveline this offseason was promising for two reasons:
1.) It shows that the Royals are more open to analytical pitching development and outside expertise, which was something that did not happen very often under previous GM Dayton Moore.
2.) It also demonstrates that Keller is doing all he can to prove to Quatraro, JJ Picollo, and the Royals front office as a whole that he can continue to be a member of the Kansas City rotation in 2023.
So far this Spring, it is hard to tell how much of his success can be credited to the curveball, especially with Statcast data not being available at Surprise Stadium, the Royals’ Spring Training home. Nonetheless, the curve has given Keller another north-south breaking offering that could play well off his four-seamer, which has become his more utilized fastball pitch over the past two seasons (in comparison to his sinker).
In fact, back in Spring Training of 2020, there were rumors that Keller was developing and in the process of implementing a curveball to his repertoire. However, due to the COVID pandemic, as well as the coaching of Cal Eldred, Keller ended up not implementing the pitch in 2020 or any season after, prior to this Spring.
A lot of the discussion this Spring has been on Kris Bubic and him not just bringing back his slider in Spring Training, but actually utilizing it in the regular season, something that did not happen in 2022 (despite all the advertisements that said he did).
Surprisingly, Keller and the introduction of his curve in both Cactus League play and in 2023 could be a bigger story, especially with Keller bound to be a free agent after the 2023 season.
Keller’s Outlook for 2023
As of now, it seems like Keller is a shoo-in for the No. 4 or 5 spot in the Royals rotation to begin the year, barring some kind of injury on Keller’s end prior to Opening Day. Daniel Lynch has also been impressive, thus solidifying for that other spot, (though to be fair, there isn’t enough of a sample for any other Royals starting pitcher to overtake Keller at this point).
David Lesky of Inside the Crown seemed to confirm that in his latest Opening Day roster projection for pitchers which was released yesterday:
With Keller in his last year of team control, it makes sense for the Royals to also start Keller in the rotation, especially if they want to up his trade value at the July Trade Deadline.
Even if Keller ends up having a bounce-back season in 2023, it could be beneficial for the Royals to trade Keller when his stock is high. This is especially true with him being 28 years old in July, and it being highly unlikely that Picollo and the Royals will ink him to a long-term extension with other younger arms in the system and on the 40-man roster.
That said, even if Keller doesn’t work out in the rotation, a possible bullpen outlook could be beneficial, especially if he can refine his slider-four seamer combo in a more limited innings role in 2023. (And it could also be a lot cheaper for the Royals in terms of an extension as well.)
When his slider command is on, it can be a dependable primary as well as swing-and-miss pitch for Keller.
The pitch produced a 29.2 percent whiff rate and a 20.4 percent K rate in 2022. Additionally, as Royals fans can see in the GIF below, his slider could get hitters, like Carlos Correa of the Twins, to chase out of the strike zone frequently as well (further evidenced by his O-swing of 33.4 percent and swinging-strike rate of 14.3 percent on the slider last year).
Could Keller become a three-pitch reliever who could find success with his slider, four-seamer, and newly-added curveball?
Perhaps. But for now, Keller will begin 2023 in the Royals rotation as a starter, especially if he continues to pitch well in Cactus League play.
And the Royals front office is hoping that he can not only help the Royals rotation improve upon their dismal performance from a season ago, but he could help the club acquire a couple of prospects in return as well by August.
Photo Credit: Nick Tre. Smith (FLO)-USA TODAY Sports
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