It’s no secret that the Royals bullpen has been frustrating for the club and fans, even with the Royals 36-25.
According to Fangraphs, Royals relievers rank 25th in ERA, 28th in WHIP, 29th in H/9 allowed, and 30th in K/9. Furthermore, according to Thomas Nestico, who runs TJ Stats (one of the more underrated analytical baseball sources), the Royals bullpen also lags tremendously in tjStuff+. This metric aligns closely with Eno Sarris’ Stuff+ and Kyle Bland’s PLV, quantifying a pitcher’s velocity and movement in one convenient number (in tjStuff+’s case, the mean is 100).
As Royals fans can see above, the Royals rank last in tjStuff+, behind even the Rockies, who rank last in the NL West.
With the bullpen reeling, many Royals fans are scouring other teams to see who could be acquired via trade. That approach makes sense, especially since the Royals are competing for a playoff spot and need proven arms to help this club clinch a place in the postseason and compete with the Guardians for an AL Central division crown.
However, while it’s tempting to look outside the organization for bullpen help, what if I told you that there are some options internally in Omaha that could impact the Royals’ bullpen right now?
Let’s look at three Storm Chaser relievers performing well now in Triple-A and could positively impact the Major League level if given a proper opportunity.
Walter Pennington, LHP
Pennington has been a fan favorite in Omaha since breaking out in the Cactus League this past Spring Training. Undrafted out of Colorado School of the Mines, Pennington has been dominant in Omaha, demonstrated by his 1.85 ERA, 0.82 WHIP, and 32.9% K-BB% in 23 games and 39 innings pitched.
The 26-year-old lefty has been so effective that the International League named him “Pitcher of the Week” recently.
Pennington is so effective because he sports a great combination of command and spin on his four-pitch mix (which includes a slider, cutter, sinker, and changeup). His 32.9% K-BB% leads all Omaha relievers who have pitched 10 or more innings this season. He also has mowed down hitters in multiple areas thanks to this prestigious command, as seen in his K% zone chart via Savant.
Pennington’s strikeout numbers are impressive because he’s doing this despite lacking premium fastball velocity.
According to Savant, his fastball pitches are a cutter and a sinker, which he throws 26.4% and 18.2% of the time, respectively. The cutter only averages 88 MPH, and the sinker averages 91.1 MPH, so they don’t sport blow-away velocity.
That said, his cutter averages a spin rate of 2,333 RPM, and his sinker has a spin of 2,2280 RPM. Those are two of the highest spin rates of any fastball pitch thrown by a Storm Chasers reliever this year.
The high spin offering complements his effective slider, which has a spin rate of 2,323 RPM and a whiff rate of 48.6%. Because of the similar and high amount of spin on his three primary pitches (slider, cutter, and sinker), hitters have difficulty adapting. That results in swings-and-misses or check-swing strikeouts like the one below.
The lack of velocity could be concerning for Royals fans, especially since the Royals need arms in the bullpen to throw gas effectively.
That said, Pennington has the right amount of spin and movement to compensate for the lack of velocity, which should allow him to be an effective reliever at the Major League level.
Steven Cruz, RHP
I didn’t list Carlos Hernandez because it’s expected that he will be up again reasonably soon (he was optioned to make space for Daniel Lynch to make an emergency start for a sick Brady Singer last Thursday). However, Cruz may be the guy for Royals fans looking for a pitcher who can throw gas effectively out of the bullpen beyond Hernandez.
Cruz averages 96.5 MPH on his fastball and sinker, throwing them a combined 65.9% of the time. That is the second-highest fastball velocity in Omaha behind Hernandez, who averages 97.1 MPH with the Storm Chasers.
Unlike Hernandez, the former Twins prospect has been able to minimize the damage on his fastball pitches when hitters do make contact.
For example, Hernandez allows a hard-hit rate of 56.3% and a barrel rate of 18.8% on fastballs this season in Omaha. On the other hand, Cruz only allows a 36.1% hard-hit rate and a 0.0% barrel rate on fastballs.
Cruz doesn’t generate the same number of whiffs on his fastballs as Hernandez, as Cruz’s 23.3% whiff rate pales compared to Hernandez’s 35.4% mark. On the flip side, Hernandez has gotten hit way harder on fastballs thrown in the middle and up in the zone in Omaha, unlike Cruz.
Let’s take a look at their fastball xwOBA zone profile charts via Savant.
On fastballs thrown right down the middle, Hernandez is giving up a 1.210 xwOBA. As for Cruz? That mark is only .156. That shows that the movement on Cruz’s fastballs makes it challenging for hitters to barrel, even if it may not generate a ton of whiffs.
Cruz is the rare pitcher who can throw high-velocity fastballs and generate groundball outs. That’s not a bad quality, especially with an elite infield defense playing behind him in Kansas City.
Even in his short tenure with the Royals in 2023, Cruz did a fine job throwing pitches 97 MPH and above and getting easy groundouts on them, like this one against the Yankees’ Gleyber Torres.
Cruz isn’t striking batters out this year at the rates he was in Omaha in 2023. However, his BB% is down from 13.9% in Omaha in 2023 to 11.8% with the Storm Chasers this year. He also is sporting a 1.22 GB/FB ratio this year, an improvement from the 0.74 mark in that category in Triple-A a year ago.
He isn’t the typical fireballing pitcher one would expect from someone of his size and toolset. Nonetheless, Cruz brings a different look to the bullpen with his fastball velocity, and he also can come in, generate groundballs, and get the Royals out of jams when the whiffs aren’t happening.
Evan Sisk, LHP
Sisk came over from the Twins along with Cruz in the Michael A. Taylor trade a season ago. The former Cardinals draft pick has yet to make his MLB debut, but he is off to a sterling start in Omaha in 2024.
In 19 games and 21 innings pitched, Sisk is producing a 1.71 ERA, 1.05 WHIP, and 27.1% K-BB%. If Pennington wasn’t so dominant, Sisk may be the most talked about left-handed reliever in Omaha.
Even with Pennington’s buzz in Triple-A, the 27-year-old lefty was named the Storm Chasers’ Pitcher of the Month for May by the Royals Player Development X account.
Sisk struggled in his first full season in Triple-A with the Storm Chasers a year ago, which makes his breakout this season encouraging.
In 58 outings and 61 innings pitched, he posted a 6.04 ERA, a 1.77 WHIP, and a K-BB% of 7.6%. The pitch mix and delivery have always been Sisk’s intriguing qualities as a pitching prospect. Unfortunately, he struggled to command the zone, as seen in this homer he allowed to the Tigers’ Parker Meadows when Meadows played for Triple-A Toledo.
Sisk has prioritized attacking the lower part of the strike zone this year in Omaha with his slider, sinker, and cutter, his three primary pitches. So far, he’s been successful in accomplishing that goal, as evidenced not only by his pitch% zone chart but also by his K% zone chart, which correlates closely with the pitch% zone chart in positive ways.
The main roadblocks for Sisk are that the Royals have plenty of lefties already in the bullpen (Angel Zerpa, Sam Long, and Will Smith), and Pennington will probably get the opportunity for a call-up over Sisk if the Royals need another lefty in the bullpen.
Nonetheless, if given the opportunity, Royals fans should not be sleeping on Sisk, who could be an effective middle-innings lefty at the Major League level. There’s a lot of Tim Hill in his profile, which wouldn’t be bad to have in the Royals bullpen, not just this year but beyond.
Photo Credit: Jill Weisleder/MLB Photos via Getty Images
