The Royals bullpen has been an ongoing issue throughout the 2024 season. As a result, the group has often drawn the ire of Royals fans this year, and the group’s 24th-ranking ERA and 28th-ranking in WHIP certainly don’t help things.

GM JJ Picollo and the Royals’ front office tried to improve the bullpen at the Trade Deadline.

They acquired Hunter Harvey from the Washington Nationals and Lucas Erceg from the Oakland Athletics without sacrificing their major prospects (though infielder Cayden Wallace and pitcher Mason Barnett certainly have potential).

Erceg has lived up to the hype, as he has two saves, struck out eight, and walked zero in 7.2 IP with the Royals. Furthermore, his high-velocity stuff has been a much-welcomed addition to a bullpen that ranks second-to-last in the league in Stuff+.

Harvey, on the other hand, has been a disappointment.

In six outings and 5.2 IP, Harvey has seen his K rate go from 26.3% with the Nationals to 17.2% with the Royals, and his K-BB% go from 20% with Washington to 3.4% with Kansas City. As a result, his ERA and FIP are 6.35 with the Royals, and he produced a -0.2 fWAR before landing on the IL due to a back injury.

Hunter Harvey’s back injury isn’t related to the spasms he dealt with two weeks ago, manager Matt Quatraro said. Harvey felt something during his pregame routine earlier this week. He was making small progress but not enough to avoid the IL.

— Anne Rogers (@anne__rogers) August 10, 2024

With Harvey’s timeline unclear, the Royals need a boost from the relievers in their organization, whether they are on the active roster or pitching in Triple-A. The Royals do not necessarily need “high-leverage” types, as Erceg, Kris Bubic, and James McArthur have handled things well since the Trade Deadline, as seen in the data set below via Fangraphs.

Could Carlos Hernandez be an option in the bullpen to boost the Royals?

Much like Harvey, he has a plus fastball and is coming off one of his best outings of the year on Friday against the Reds. After giving up a leadoff double, he struck out the side to close out the Royals’ 7-1 victory.

In his second outing since being promoted on August 10th, Hernandez showed impeccable control, which isn’t exactly a calling card for him as a pitcher.

Let’s examine the changes Hernandez has made since returning to Kansas City and how his presence (and Harvey’s absence) could affect the Royals’ bullpen for the remainder of the season.

Hernandez was called up after Harvey and John Schreiber landed on the IL. Hernandez may only be a temporary option until Harvey or Schreiber return from the IL. If he continues to pitch well, it will be tough for Picollo to send him back to Omaha.

In two outings since being called up, he’s been sensational.

He has a K/9 of 15 in three IP, a 3.00 ERA, and a 0.84 FIP. They haven’t been high-leverage appearances (his other outing was during a Twins blowout of the Royals on August 12th). That said, it’s nice to see Hernandez limit the damage in his recent outings, something he’s struggled with the past two seasons.

An intriguing development for Hernandez in this recent call-up is that he’s been relying more heavily on his four-seamer and curveball and less on his slider and splitter. In his last outing alone, he threw his curve 15.8% of the time and his slider only 10.5% of the time.

For the season, he’s been throwing his slider 20.9% of the time and his curve only 13.2% of the time. However, in Omaha, his curve usage was 19.2%, and his slider usage was 12.9%. Therefore, the Royals’ pitching development team seems to have encouraged higher usage of the curve, and Friday’s outing was the first step at the MLB level.

The four-seamer has been his best pitch this year on a PLV end, but his other three pitches have had mixed results (especially his splitter, which has had poor pitch quality this year).

The slider and curve have been pretty similar at the MLB level. Conversely, the curve has shown better potential in Omaha on a pitch quality end, as seen in the MiLB pitch quality data comparison below.

As evidenced by his xZone%, Hernandez’s curveball was a much better-breaking offering for generating strikes. Furthermore, he also showed a better break with the curve in both the vertical and arm-side areas. It will be worth watching from Hernandez in this stint with the Royals if his Triple-A movement data starts transitioning to the Major League level.

Omaha Kansas City

The slider and curve both displayed a lot more horizontal break in Omaha than they did with Kansas City this year. We started to see more of that horizontal movement in Hernandez’s recent outings, especially in this strikeout on Friday night against Cincinnati’s Jeimer Candelario.

For context, let’s examine his curveball from late May when he pitched against the Twins at Target Field.

Hernandez’s curve is more of a vertical offering. However, it can be easily hit and hard to boot if it’s not located well. That said, the curve has a lower hard-hit rate (40%) than the slider (45%) and a lower wOBA (.244 to the .409 mark on the slider).

Utilizing the curve as his primary breaking offering could help Hernandez fully tap into his potential and be the backend reliever the Royals need in low to medium-leverage situations.

Schreiber is expected to return to the Royals soon as he is on a rehab assignment in Northwest Arkansas. As an opener, he looked solid as he struck out two in two innings of work.

John Schreiber struck out two in his inning of work in Northwest Arkansas on rehab!

RHP Ben Kudrna is on in relief! pic.twitter.com/2HRdGz9yRF