Royals Bullpen Internal Options: Regression Risks & Paths Forward for 2026

In my last article, I examined the unusual case of Tyler Rogers (Why The Royals Should Sign Quirky Submariner Tyler Rogers). As discussed there, while Rogers may be an outlier because of his unorthodox mechanics, it is not typically a good strategy to rely on pitchers who lack swing-and-miss stuff and instead rely on generating soft contact to get outs. Despite a bullpen that ranked third in Save%, statistics indicative of swing-and-miss ability, like K% and Whiff%, paint a far less optimistic picture for repeating that success in 2026 with the current cast of candidates.

According to FanGraphs, the 2025 Royals bullpen ranked 28^th in K% (20.5%), was in the middle of the pack in BB% (8.3%), and ranked 24^th in both xFIP (4.21) and K%-BB% (12.2). They benefited from a .284 BABIP (batting average on balls in play; 8th-lowest in MLB) and a 74.6% left-on-base percentage (LOB%; 3rd-highest), well above the league average of 72%.

All of this tells me what my blood pressure metrics told me every time Carlos Estevez came in to protect a one-run lead…. The Royals' pen got more than a bit lucky and is ripe for regression. This "luck" in stranding runners and low BABIP added an estimated 0.38 runs to their ERA performance vs. xFIP and represents a major regression risk for 2026 without improvement in peripheral statistics.

Estevez is the poster child of the group, posting just a 20.1% strikeout rate, a 77.6% LOB rate, and a .234 BABIP and a xFIP that was more than double his actual ERA (2.45 vs 4.95)! His K% in 2023 and 2024 were much better, at 27.8% and 23.6%, respectively.  Unless those K% numbers come back to his 2024/2024 levels, Estevez’s career FIP of 3.99 is very likely a much stronger indicator of his success in 2026 than the identical 2.45 ERAs he has posted the last two years.

Estevez’s slider is his best pitch by Stuff+ estimates, and he has increased his usage of it consistently since the 2022 season. His four-seam fastball is average by Stuff+ and was down slightly to 95.9 mph in 2026 from his career average of 97.1. The decrease was mainly due to lower velocity in April, and it increased as the season progressed, but it remains something to keep an eye on in his age-33 season. Also of concern, his SwStr% of 8.2% last year was a career low.

Lucas Erceg, number two in Matt Quatraro’s circle of trust, similarly struggled with his peripheral stats while still somehow managing to limit runs scored. After posting strong K/9 numbers in his first two MLB seasons (10.8 K/9), he dropped off significantly to 7.0 K/9 in 2025. Concerningly, his Whiff% dropped from an elite level of 31.9% in 2024 to 24.7% in 2025. As the 2025 season progressed, Erceg never looked quite right, and he went on the injured list first with a back issue in late May and later with a shoulder impingement injury. The Royals need the healthy, bat-missing version of Erceg in 2026. If Estevez regresses, Erceg will need to step back into the closer role.

John Schreiber turned in another decent season and will be counted on again in 2026. He led all Royals relievers (with over 50 IP) in K%, 23.4% and K%-BB%, 16.2%. He’s never managed to match his early career K% numbers, and his Whiff% was below average at 23.4%, but he has established himself as an above-average reliever entering his age-32 season.

Angel Zerpa returns in 2026. Stuff+ metrics love his sinker and slider. He has middling 21.1 K% and 8.0 BB% numbers, but a 2nd-percentile Whiff% of 16.4. He gets by on a 99^th percentile ground ball percentage of 63.7. Despite 96+ mph four-seam/sinker velocities from the left-hander, he misses very few bats.

Daniel Lynch IV, like Zerpa, is a left-handed pitcher with high ground-ball rates and low whiff rates, just not as extreme as Zerpa's. His 2025 season 15.5 K% and 9.0 BB% rates are not headed in the right direction, and his roster spot may very well be in jeopardy.

Steven Cruz is a big young right-hander obtained in the Michael A. Taylor trade with the Twins, who has struggled with command thus far in his career. He possesses elite fastball velocity along with good extension provided by his 6’7” frame. All three of his pitch offerings in 2025 were rated by Stat+ as well above average. His four-seamer had an average velocity of 98.2 mph and a Stat+ mark of 121, while his cutter had a 107 Stat+ value, and his slider was even better at 125. His Location+ of 83 and his 9.5 BB% are a good indicator of where he had some issues. Despite his impressive velocity and stuff, his Whiff% and K% were both just OK (24.3%, 20.1%). Cruz took some significant steps forward in 2025 before also ending his season on the IL. Unlocking his potential will be important if the Royals' pen is to improve in 2026.

The Royals signed local kid Alex Lange to a near league minimum “prove it” contract after he was designated for assignment by division rival, the Detroit Tigers. Lange was a key member of the Tigers' bullpen in 2022 and 2023, saving 26 games in ’23 before suffering a lat injury that required surgery in 2024. When healthy, Lange features a curveball-heavy repertoire along with a 96 mph fastball, a sinker, and a changeup. In 2023, that repertoire led to a whiff rate of 39.1%, which ranked in the 99th percentile. Unfortunately, it was accompanied by a 1st percentile BB% of 15.6%. The signing of Lange should be taken as a tacit admission by the Royals of needing more guys with power swing and miss stuff, even if there is a tradeoff in walks.

Former 2nd-round pick Jonathan Bowlan was part of the college pitching-heavy 2018 class that included Brady Singer, Kris Bubic, Jackson Kowar, and Daniel Lynch, along with Jonathan Heasley and Austin Cox. For a time, it appeared that Bowlan might be the best of the bunch. He threw a no-hitter for Wilmington in 2019, starting 23 games between Low A and High A, and striking out 150 in only 146 innings. Bowlan lost the 2020 season to COVID and then appeared in only four games in 2021 before losing that season to Tommy John surgery.

He struggled in 2022 and 2023 before regaining some measure of success with Omaha in 2024. Bowlan spent the 2025 season traveling back and forth between Omaha and Kansas City and put up decent numbers at both stops.  At 6’6”, Bowlan has good extension and above-average velocity. He features a 5-pitch mix from his starting days, but as a reliever, he is primarily a four-seam fastball and slider pitcher, mixing in a sinker, curveball, and changeup. His Stuff+ metrics are above average for Stuff+, Location+, and Pitching+, with his slider being his highest-rated pitch. Perhaps because he pitched mostly in low-leverage situations, I didn’t realize his metrics were as good as they were. His Whiff Rate was elite at 33.7, his K% good at 25.6, and he got a lot of ground balls. His BB% was high at 9.4, and at 29, the ceiling is somewhat limited, but he has earned the opportunity for a second look.

Luinder Avila debuted in 2025 and looked good in doing so. His 2025 Baseball Savant Pitching Percentile rankings are a sea of red, with only his walk rate being poor. It should be noted that these are based on only 14 innings pitched, though. He has a good frame with nasty movement on his breaking pitches, along with more than adequate fastball velocity. He is a potential breakout bullpen candidate this year.

Eric Cerantola was added to the 40-man roster last year to protect him from the Rule 5 draft after a successful season at Omaha. He’s another big kid with a big arm. He’s struck out 11.9 batters per nine innings in his minor league career, but also has had his share of command issues with 5.4 BB/9. An athletic Canadian with a background in hockey, he is a fastball-slider pitcher who throws an occasional curve. His slider is arguably the best in the upper-level Royals minor league system and has received 70 grades. He may be this year’s Jonathan Bowlan, shuttling back and forth from Omaha as needed.

Relief pitcher performance year-over-year is inherently volatile.  Undoubtedly, the Royals got lucky in 2025, which screams regression in 2026. For that not to happen, some of the internal options currently on the roster need to step up. The Royals probably also need to add more options from the free agent and/or trade market. Stay tuned for that in Part II.