Early this morning, Bob Fescoe of 610 AM Radio reported that Royals pitcher Zack Greinke would indeed come back to Kansas City for at least one more year, per Twitter:
Later in the morning, nearly every major reporter, including Ken Rosenthal and MLB.com Royals beat writer Anne Rogers, confirmed Fescoe’s report. In addition, Mark Feinsand also revealed possible details of the deal, mentioning that the one-year base contract is likely to be in the $8-10 million range, though there will be “performance” incentives that could give him an opportunity to earn more by the conclusion of the 2023 season.
Greinke is certainly nearing the end of his career, as he posted a career-low K rate (12.5 percent), and the third-worst K-BB rate (7.9 percent) of his career as well, according to Fangraphs. While he did post a 3.68 ERA and 1.9 fWAR over 26 starts and 137 innings of work, his 4.03 FIP and 4.73 xERA suggest that he benefitted from some batted ball luck in his return to Kansas City in 2022.
In addition, most preseason projection models are not optimistic that Greinke will have a great 2023 either. Steamer projects a 4.56 ERA and 0.9 fWAR, while The Bat projects the same fWAR, but a much higher ERA (4.78). ATC was the most optimistic, projecting a 4.39 ERA and 1.0 fWAR.
Safe to say, it’s likely that Greinke’s days of being the Royals’ ace are behind him. In fact, it would not be surprising to see him by the conclusion of Spring Training start the season as the No. 3 starter in the rotation, behind Brady Singer and Jordan Lyles.
While Greinke may be entering what could be his “final” season in Kansas City (and professional baseball in general), he still brings a veteran presence to the rotation as well as an ability to eat innings in a crafty fashion. The strikeouts were not plentiful last year, but Greinke proved that he could be a force at Kauffman Stadium last year, as evidenced by his home and away splits, via Fangraphs.

Therefore, it is hard to imagine this Royals rotation without Greinke this season, even if he may not be at the top like he was in 2022 (though Roster Resource is projecting him to be the Opening Day starter).
And hence, it will be interesting to see how the rest of the Kansas City Royals rotation develops, especially during Spring Training in Arizona.
Could Keller and Yarbrough Settle In As “Swing Men”?
Right now, it seems set that the Royals rotation will consist of Greinke, Singer, and Lyles, barring some kind of injury in Spring Training.
Other than those three though, there will be plenty of arms battling for those two other spots in the rotation at the Royals camp in Surprise.
Essentially, there are two categories of pitchers who will be competing for those remaining spots: the veterans and the young candidates.
Let’s take a look at the first category, which essentially consists of Brad Keller and the newly-acquired Ryan Yarbrough. Keller will be 28 in July, and Yarbrough just turned 31, which would make them the oldest starting pitcher candidates beyond Greinke (39) and Lyles (32).
Roster Resource projects that Keller and Yarbrough will both make the rotation, and I can understand that, especially since they have more starting pitching experience in comparison to the other young starters on the Royals’ 40-man roster. However, both Keller and Yarbrough are coming off disappointing ends to the 2022 season which resulted in them both ending up in the Royals and Rays’ bullpens, respectively.
Last season, Keller posted a 5.09 ERA and 1.79 K/BB ratio in 35 appearances, 22 starts, and 139.1 innings pitched. While it was a disappointing season at the surface level, much like 2021, a deeper look into his numbers should give some room for optimism.
His FIP for the year was 4.50 and his xERA was 4.37. Not only were those numbers better than his ERA, but they were also better than his 2021 marks in those categories as well (4.72 FIP; 6.47 xERA), according to Fangraphs.
Keller was also much better at the beginning of the 2022 season, and that is evidenced in both his monthly splits, as well as first vs. second half numbers, which can be seen below, via Fangraphs:

It’ll be interesting to see if new manager Matt Quatraro and pitching coach Brian Sweeney can help Keller figure out these second-half issues. Is it just fatigue, and him conserving his stamina throughout the year? Or does Keller need to make an adjustment in his pitch mix or shape to make him less hittable as opposing teams get better scouting reports against him throughout the course of the season?
There certainly is an argument to be made that some changes in his pitch grip could help him accomplish the latter in 2023.
As for Yarbrough, the big key for him will be health. He started the year poorly for the Rays but got better over the course of the year once he got back to full health (albeit more in a bullpen role).
Here is a look at his own monthly and first-half vs. second-half splits from last season in Tampa, via Fangraphs, and that seemed to confirm that he was much more comfortable after the All-Star break.

Yarbrough doesn’t sport a great fastball, as it averages under 90 MPH (86.8 MPH last season, according to Fangraphs). That being said, he does sport a nasty slider, which makes him an intriguing option in the rotation, especially from the left side.
Nonetheless, while Keller and Yarbrough offer higher floors as rotation options in Kansas City in 2023, their splits data from last season demonstrates that they would be better off in “swingman” spots in the pitching staff (i.e. relievers who make spot starts) rather than full-time starting pitchers.
If Keller and Yarbrough have to make 20+ starts in a season, batters will eventually get to them. The data from last season shows that especially for Keller and somewhat for Yarbrough, who posted a 5.11 ERA in 21 starts and 155 IP in 2021. Yarbrough was much better in 2022 when he primarily pitched in relief, with the occasional start here and there when needed.
Yarbrough is proven already as a “swingman” from his days in Tampa Bay. Keller hasn’t really been utilized properly in that spot by former manager Mike Matheny. Safe to say though, I am not sure Matheny was skilled in utilizing pitchers in such a role either.
Quatraro has experience being on a staff in Tampa that succeeded with such pitchers from his time as the Rays’ bench coach. And if he can get Yarbrough and Keller to produce as “swingmen” out of the bullpen?
Well, the Royals could still properly develop their young starters, while still having insurance for long relief and spot start help, especially if the Royals starters struggle early in starts, as they had a tendency to do last season.
Keller and Yarbrough will ensure that their middle and late-inning relief group is less taxed over the course of the season. And that’s more important to have for this squad than either of them getting the No. 4 or 5 spot in the rotation.
So Which Young Royals Pitcher Gets The Spot(s)?
With Keller and Yarbrough better utilized in a “swingman” role, that leaves one to two spots left for either Daniel Lynch, Kris Bubic, Jon Heasley, Angel Zerpa, Max Castillo, or Jackson Kowar.
Let’s just whittle away the obvious candidates for now.
Zerpa and Castillo most likely will begin the year in Omaha. While they offer aggressive approaches, their overall pitch mix and shapes still need work. The Royals’ pitching development team would rather work on that in Triple-A than the Majors, especially with Zerpa and Castillo both being 23 years old.
As for Kowar, I have a feeling he may start in Omaha, but this time, he will begin work as a reliever. While it seems crazy to give up on him as a starter for now, I am not sure if he has the command or makeup to make it as an MLB starter after two rough years at the MLB level (and some regression in Omaha in 2022).
On the flip side, he has the stuff to work as a lights-out reliever, and I think in a year or two, Kowar could have a similar role in the Royals bullpen as Luke Hochevar in 2013 and 2015.
So with Zerpa, Catillo, and Kowar out of the way, that leaves the last one to two spots in the rotation to Lynch, Bubic, and/or Heasley.
Lynch seems to be the most likely candidate to earn one of the final spots in the rotation.
He showed flashes of brilliance in 2022, especially in April. He posted a 3.38 ERA in the first month of play, according to Fangraphs, before struggling for most of the year (though he did bounce back somewhat in August with a 3.94 ERA that month).
Most of Lynch’s issues feel mechanical, and an adjustment or two this Spring could help him not just make the Opening Day rotation, but perhaps be the No. 2 guy behind Singer in the long term.
When he is on, there are very few pitchers in the organization as impressive as Lynch, especially at the MLB level.
Choosing between Bubic and Heasely may be a difficult dilemma for the Kansas City coaching staff. However, I think Royals fans should be more optimistic about Bubic’s outlook for 2023 than Heasley’s right now.
While Heasley’s fast approach on the mound should be appreciated (especially with the impending pitch clock), his lackluster K/BB ratio (1.49) and CSW rate (22.5 percent) should make Royals fans dubious that he can be a starter for much longer at the MLB level. It wouldn’t be surprising to see Heasley follow Kowar to the bullpen sooner rather than later, though I do think Heasley will start in Spring Training in the rotation (and likely transition that to Omaha, barring an injury to Singer, Lyles, or Greinke).
And that’s not a bad thing. Heasley could be a very solid middle reliever in the long run. In short stretches, Heasley showed that he could challenge and be effective against MLB hitters last season (especially when he can primarily utilize his slider):
That would leave the final spot in the rotation to Bubic, but he has to earn it and show more confidence and effectiveness with his slider, which he didn’t utilize as promised in 2022.
In fact, how Bubic showcases that fourth pitch this Spring in Cactus League play could determine whether or not he makes the rotation out of Spring Training.
Bubic has struggled against lefties over his career, primarily because his only-breaking offering (curveball) just isn’t effective against hitters from that side of the plate. He needs to make an adjustment, and I’m guessing Sweeney and the Royals pitching development team have already been in talks with Bubic this winter about utilizing and developing that slider as soon as pitchers and catchers report to camp in February.
If Bubic flashes the slider and is effective and confident with it in Cactus League play, expect him to take the last spot in the rotation.
If he struggles with it, it is likely that he will start the year in Omaha where he will continue to work on the pitch, much like Singer did with his changeup in Triple-A last season.
And if that’s the case, it is plausible that Quatraro would have Keller and Yarbrough filling in that fifth spot in the rotation on a matchup-by-matchup basis, until Bubic is ready to transition his four-pitch mix to the MLB level in 2023.
Unless of course, Heasley (or Zerpa or Castillo) really performs out of the gate in Cactus League play or Omaha.
The Royals have options to throw in the rotation this season…
And that is something that Royals fans haven’t been able to say in quite some time, if ever in the new Millenium.
Photo Credit: Jay Biggerstaff-USA TODAY Sports
I feel kinda lost attempting to forecast this pitching staff, but not necessarily in a bad way. With the new coaches, it’s going to take some to get a feel for everything, but I’m optimistic we’ll finally see some significant progress with at least some of Lynch, Bubic, Kowar, etc. And I don’t think it’s ever a bad thing to have Greinke around, especially if we’re realistic about what version we’re getting. I get being hesitant about him taking innings away from young guys, which might be the case early, but MLB pitching is so volatile now that I would bet it works out in the long run.
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