Should Carlos Hernández Return to the Royals Bullpen?

The Royals experienced their first loss of the Cactus League season on March 25th, as they fell 8-4 to the Texas Rangers in Surprise:

Carlos Hernández made his first Cactus League appearance on Friday and had an inconsistent performance against the Rangers lineup. In 2.0 IP, Hernández did strike out two batters and walked none, but he also gave up three runs on four hits, which included two home runs.

Here’s one that Rangers leadoff hitter Brad Miller hit off of Hernández on the first pitch of the game to start off the game:

While it wasn’t a horrendous performance by any means for Hernández, it will be interesting to see how he fares this Spring, especially with so many pitchers competing for spots in the Opening Day rotation.

Jackson Kowar, who also is competing for a rotation spot, didn’t have much better of an outing than Hernández, as he too gave up three runs on four hits in two innings of work against the Rangers. So, Royals fans can say that Kowar isn’t any more deserving of a rotation spot right now than Hernández.

Hernández showed some flashes of being a quality starter in 2021 (which one can’t say for Kowar in 2021). That being said, would the Royals be better off utilizing him in the bullpen in 2022, in perhaps some kind of hybrid long/middle relief role who could pitch for multiple innings, especially if a starter is blown up in the first couple of innings of a game?

Or should the Royals continue to develop Hernandez as a starter to at least begin the season? After all, Roster Resource believes that he will be the No. 5 starter in the Royals rotation on Opening Day.

When looking at his 2021 splits, it may be a more challenging question than the Royals and Royals fans may want to admit.


After throwing 14.2 innings during the shortened 2020 COVID season, Hernández accumulated 85.2 IP in 24 appearances in 2021, which included 11 starts. At the surface level, his 3.68 ERA and 1.0 fWAR overall are encouraging numbers, especially since Hernandez hadn’t pitched above low-A ball prior to 2020.

However, it’s really interesting to see how Hernández’s numbers look when broken down over the variety of situations he pitched in for the Royals pitching staff last season.

In 2021, he was a surprise addition to last season’s Opening Day roster, and started out the year in the Royals bullpen (he actually earned the win on Opening Day in what ended up being the longest Opening Day game in Royals history). Unfortunately, the native Venezuelan pitcher struggled with control, which is demonstrated in his 20 percent walk rate in his appearances from April 1st to May 29th.

Here’s a look at how his other Statcast data looks over that same timespan:

What’s interesting to see is that while his walk rate was a bit out of control over that timespan, he did limit hard hits (33 percent) as well as barrels (zero). Furthermore, his xBA (expected batting average) of .171 showed that he may have suffered from some rough batted ball luck at the beginning of the year.

When Hernández got called up a second time in the year, he looked a lot more comfortable on the mound at the Major League level, especially from June 12th through July 6th.

Over that timespan, he still pitched out of the Royals bullpen, but here’s how his Statcast numbers looked over that near month of play:

Granted, hitters hit the ball harder (55 percent hard-hit rate; 90.3 MPH exit velocity on batted balls) and barreled more balls as well (three percent home-run rate; five barrels). That was a lot worse than what was happening against him at the beginning of the season.

On the other hand, he lowered his walk rate by eight percent, increased his strikeout rate by four percent, and his batting average actually out-performed his xBA by 15 points.

A big contributor to that was him being able to locate his four-seamer a lot better over that second period of time as a reliever at the MLB level. Even though he was pumping it in the 100 MPH range in both stints, he wasn’t quite throwing it in the strike zone on a consistent basis the first time around in early April and late May.

Here’s a look at his four-seam fastball heatmap from April 1st to May 29th, via Baseball Savant:

While he is hitting that lower glove-side part of the strike zone, Royals fans can see from all the other blue areas that he was pretty wild with his four-seamer.

Here’s a look at him failing to hit the strike zone against Mitch Garver of the Twins, despite pumping 100 MPH on the four-seamer:

Now, let’s take a look at Hernández’s heatmap in his second stint out of the Royals bullpen from June 12th through July 6th:

There’s more red on this heatmap, and specifically, more red in the strike zone as well. That’s a good thing, especially for a pitcher like Hernández who has the triple-digit capability with his four-seamer.

Let’s take a look at Hernández pumping that four-seamer up in that red dot of the strike zone, as he gets Skye Bolt of the Oakland Athletics to swing and miss for the strikeout to end the inning.

So Royals fans can see the positive adjustments Hernández made, especially with his four-seamer, from one bullpen stint with the Royals to the other.

But what did it look like when he moved to the Royals rotation after the All-Star break?


After the All-Star break, Hernández took a spot in the Royals rotation, and in 58.1 IP as a starter, he posted a 3.55 ERA. However, here’s what his Statcast metrics looked like from July 16th to his last start of the 2021 season on September 24th:

There are some positive things to be had from his stint as a starter, especially when looking at the splits data from Fangraphs as well as Savant. He did lower the hard-hit rate by 13 percent from his second bullpen stint, and the average exit velocity also went slightly down as well (in addition to the launch angle on batted balls).

However, the strikeout rate dropped by a considerable margin, 15 percent to be specific.

For a pitcher who relies on such high velocity, having a sub-20 percent K rate as a starter is not a recipe for success at the Major League level.

Granted, some regression on the K rate was to be expected in the move to a starting role. Any pitcher needs to conserve themselves, especially if they want to get to the 5th innings and beyond. But a double-digit decrease is a bit alarming, especially since the walk rate didn’t drop all that much (12 to 10 percent as a starter).

When it comes to his command of the fastball as a starter, he was much better at locating in one specific area of the strike zone: the upper arm side area.

Here’s a look at his heatmap from July 16th to September 24th:

Notice how big that red dot area is in that upper left part of the zone. That’s a good sign that he’s able to pound strikes with ease as a starter, which is much needed for any starter in order to maximize innings on the bump.

Unfortunately, though, Hernández as a starter relied more on hitters “just missing” his four-seamer rather than overwhelming them in “hard-to-hit” areas of the strike zone, which was more the case during his second stint.

Here is an example of Hernández throwing a 95 MPH four-seamer in a very hittable part of the strike zone to Luis Robert of the White Sox.

A hitter of Robert’s caliber should mash this pitch.

Instead, he’s a little late and gets under it, and instead flies out to right fielder Edward Olivares at Kauffman Stadium.

That won’t happen very often in 2022, especially with hitters having more of a scouting report on Hernández going into this season.

Maybe Hernandez was just feeling fatigued down the stretch after pitching his first full professional season since 2019. Maybe he was just trying to focus more on command in the transition to starting rather than getting hitters to swing and miss like he did in the first half.

Either way, the Royals have a tough decision to make with Hernández, especially with so many young pitchers vying for starting innings on the Major League roster this Spring.


It wouldn’t be a disaster by any means to start Hernández in the rotation to begin 2022. At the very least, he proved he could throw strikes and minimize the walks as a starter, which is much-needed considering that the Royals ranked last in the league last year in starting pitcher BB/9.

However, with Daniel Lynch and Kowar not really having much to prove in Omaha in 2022, Hernández did prove last season he could at least fluidly rotate between the rotation and bullpen on a whim. He did that at times during his second bullpen stint, finding a role as a guy who could go multiple innings after the starter was pulled early, or filling in the middle or late innings in higher leverage situations.

Hernandez may not be closer material just yet, but his pitch mix and triple-digit stuff could make him an excellent one for years to come, should he get the opportunity in the near future.

The Royals have a good one in Hernández. However, it’s difficult to picture what his exact role in Kansas City will be in 2022 and beyond.

Let’s see if he can have a much better second outing this Spring.

If it’s more of the same, then the Royals may think about getting creative with Hernandez sooner rather than later.

Photo Credit: Kamil Krzaczynski-USA TODAY Sports

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