While watching the Phillies’ 7-0 win, one player primarily stuck out to me amidst the Phillies’ barrage of home runs against Houston’s Lance McCullers, Jr. (a fan favorite of Royals fans when it comes to “hate-ability”).
And surprisingly enough, that one player wasn’t a Philadelphia hitter.
Rather, it was Phillies starting pitcher Ranger Suárez, who pitched five shutout innings against the Astros and struck out four batters while allowing only three hits and one walk in the winning effort.
What stood out to me from Suárez’s performance on Tuesday evening was the data from his player breakdown, via Baseball Savant, which can be seen in the table below:
Suárez was certainly impressive on a called-strike plus whiff (CSW) rate end, as he generated an overall rate of 30 percent over 76 pitches. But he wasn’t dominant on a swinging-strike end by any means against the Astros.
His whiff rate was only 22 percent overall, and his primary pitch (his sinker) didn’t generate a single whiff on the night, even though it produced an overall CSW rate of 31 percent.
Unlike Phillies aces Zack Wheeler and Aaron Nola, who certainly have commanded more attention this season and postseason run, Suárez has quietly become one of the Phillies’ most productive pitchers over the past two seasons.
According to Fangraphs, Suárez has accumulated a 5.3 fWAR over 68 appearances and 261.1 IP since the start of the 2021 season. He produced a sterling 1.36 ERA in 2021 (though he only made 12 starts) and even though in his first full season as a starter his ERA bumped up to 3.65, he still produced a 3.87 FIP, which is still solid, especially for a middle-of-the-rotation pitcher who doesn’t generate a high number of strikeouts (7.47 K/9 in 2022).
One of the reasons Suárez sticks out to me as a Royals fan though isn’t due to his pitching prowess necessarily, or that I think he could be a trade or free agent target for GM JJ Picollo in the near future.
Rather, he is the kind of pitcher that Royals pitcher Angel Zerpa could perhaps develop into as soon as 2023, if healthy.
Because Suárez and Zerpa’s pitching skillsets and styles appear incredibly similar. And that type of pitcher, which Zerpa could develop into, would not just be welcomed in the Kansas City rotation in 2023, but perhaps needed if the Royals want to turn things around in the Central division within the next couple of seasons.
Unlike Suáarez, there isn’t a lot of MLB data to measure Zerpa at this point in his career.
Zerpa has only accumulated four outings and 16 innings pitched across two seasons (2021 and 2022). While his ERA is impressive at 1.13, his FIP is much higher at 4.63, which is a big reason why he’s only produced an fWAR of 0.1 overall for his career thus far.
Zerpa’s 2022 season was a mixed bag of sorts, even across a limited sample.
In his first outing of the year against the Detroit Tigers on July 11th, he pitched two innings of relief and allowed zero runs and no hits and walks. However, he didn’t record a single strikeout, and his CSW rate data was a bit questionable as well, as evidenced in the player breakdown data from Baseball Savant.
A whiff rate of seven percent and a CSW rate of 19 percent certainly isn’t impressive by any stretch of the imagination. In addition, it is a sign that Zerpa benefited a bit from batted ball luck that outing. That point was especially illustrated by a Miguel Cabrera hard-hit ball that had an expected batting average of .820, but ended up being just a long fly ball out, which can be seen below:
Zerpa was much better in his first start of the year, which came against Toronto in Canada when the Royals had 10 players out due to their unvaccinated status. Zerpa went five innings and allowed only one run on four hits, and two walks while striking out two. Both of Zerpa’s strikeouts came on the slider, which produced check-swing punchouts.
Here’s a look at one of Zerpa’s two strikeouts, which came against Jays hitter Teoscar Hernandez:
Zerpa’s final outing of the year against the Angels at Kauffman on July 26th didn’t go as well as his previous start against Toronto, but it was decent enough nonetheless. He only went four innings and allowed a run on four hits, and one walk, while striking out one. While he did strikeout Angels superstar Shohei Ohtani in the first inning, Ohtani returned the favor later in the game with a monster home run over the centerfield wall at the K:
Unfortunately, his outing against the Angels was his final of the season, as he exited the game due to a knee injury, and ended up being placed on the 60-Day IL nearly a week later, which pretty much ended his season.
One thing Zerpa and Suárez have in common is that they don’t generate a ton of whiffs, and they have trouble getting opposing hitters to chase.
According to Savant, Suárez ranked in the 25th percentile in chase rate a season ago, and he also posted a CSW rate under 26 percent (26 tends to be the league baseline roughly for starting pitchers). Surprisingly, even though Suárez had more innings, Zerpa’s plate discipline metrics didn’t look all that different from the Phillies starter.
Suárez was much more effective when it came to getting swings and misses and chases, as well as limiting contact.
Here’s an example of Suárez illustrating both of those two strengths in this swinging strikeout of Brandon Drury in the NLCS which comes on a changeup out of the strike zone:
On the other hand, Zerpa was much better at generating strikes, especially called strikes and strikes early in the count (F-Strike percentage).
Another sign that Zerpa could perhaps project into a pitcher like Suárez in the future is that they both work quickly on the mound, which is going to be much-needed with the pitch clock expected to be implemented next season at the MLB level.
Zerpa last year averaged 19.1 seconds between pitches. Suárez averaged 21.6 seconds between pitches. To compare, Suárez’s rate would’ve been the median for Royals starting pitchers last year. As for Zerpa, his pace was actually the second-fastest of any Royals starting pitcher a year ago, according to Fangraphs.
Considering Zerpa has less than 20 MLB innings under his belt, the fact that he is sharing so many similarities with Suárez already is a positive sign for Zerpa and his outlook in the Royals rotation in 2023 and beyond.
Now, Zerpa and Suárez aren’t carbon copies of each other, at least not yet.
Zerpa relies more on the four-seamer and slider as his primary fastball-breaking ball mix, while Suárez relies on a sinker-curveball combo. Suárez also possesses a few more pitches in his arsenal, as he sports six total pitches, including a changeup, cutter, four-seamer, and slider. As for Zerpa, he has a changeup and sinker to go along with his primary pitch combo.
Here’s a look at both Zerpa and Suárez’s pitch breakdown by count, via Savant, and Royals fans should notice the difference in pitch variety between the Royals rookie and Phillies starter:
(Scroll to the left for Zerpa; right for Suárez.)
It will be interesting to see if Zerpa will continue to utilize his four-seamer and slider as his primary pitches, or if he’ll perhaps utilize the sinker and slider more often, much like Suárez. Early in his career, the Phillies pitcher primarily relied on his four-seamer, but he changed course after the 2018 season, and he’s relied primarily on his sinker at the MLB level ever since 2019.
It makes sense that Suárez would utilize his sinker more, as he doesn’t necessarily possess a high-velocity, strikeout arsenal. And thus, the sinker allows him to generate more weak contact and groundballs, which is confirmed by his career 56 percent groundball rate.
Zerpa’s career groundball rate is solid at 49 percent, but it could be as high as Suárez’s with the appropriate adjustment in pitch mix this offseason and Spring. It will be interesting to see if tweaking his pitch mix will be a priority with the Royals’ new pitching coach (and perhaps a new pitching development team) this off-season. Zerpa has all the tools to be as effective a starting pitcher as Suárez in the long term, but he won’t do it with his current pitch arsenal.
But Zerpa has the pitches and tools to find such similar success. He just needs to stay healthy and make the right changes with his primary pitch mix in 2023…
And if he does get that necessary help and coaching, then the Royals may have a middle-of-the-rotation starter who can provide the Kansas City rotation a lot of quality innings for years to come, 2023 included.
Photo Credit: Jon Blacker/The Canadian Press via AP
The Royals Reporter 
[…] On one hand, Zerpa works fast and may have the best command of this tier (Zerpa has at least proven it at the MLB level). There’s an aggressive and fearless nature to Zerpa’s approach on the mound, and earlier this offseason, I compared Zerpa’s outlook to Philadelphia’s Ranger Suarez. […]
LikeLike
[…] Zerpa has flashed potential at the Major League level, mostly thanks to his pinpoint control and quick approach on the mound that makes up for a lack of swings and misses (at least at the big league level). However, he has been dogged by injury recently, as he was shut down at the end of the year due to a knee injury, and now he has been set back by a shoulder injury that prevented him from making any appearances this spring. […]
LikeLike