The Royals’ pitching staff has been an adventure this season, and not in a promising way.
The pitching as a whole ranks 28th in ERA and 26th in fWAR, according to Fangraphs, as of June 27th. While some growing pains were to be expected under new manager Matt Quatraro and pitching coach Brian Sweeney, the progress has been small at the Major League level this season (though the results have been far more promising at the Minor League affiliates, as seen below).
Despite the Royals’ overall pitching struggles though, there have been some encouraging stories, especially as of late.
After missing the start of the season due to injury, former 2018 Draft pick Daniel Lynch has emerged as one of the Royals’ better-starting pitchers this month, as he is posting a 3.96 ERA in six starts and 36.1 innings of work. His progress this season is encouraging in light of Brady Singer’s struggles and Kris Bubic’s Tommy John surgery (who are also fellow 2018 picks).
Another early success story, ironically from the 2018 draft class as well, is Austin Cox, a former 5th-round pick out of Mercer.
Cox has long been a bit of a polarizing prospect in this Royals system, as he was hyped back in 2019 and 2020, but regressed in a big way in 2021 and 2022. His 3.00 ERA in Northwest Arkansas in 2021 and 4.21 ERA in Omaha in 2022 didn’t match his 5.12 xFIP and 5.49 xFIP at those levels, respectively, which shows that he likely benefitted from some batted ball luck at those levels over the past two years.
As a result, Cox was not added to the 40-man roster when initially eligible which left him exposed to the Rule 5 Draft the past couple of seasons. Thankfully for the Royals, he wasn’t drafted, and that has not just proved to be a benefit to this Royals pitching staff this season, but also as a missed opportunity for clubs who had selections in the Rule 5 Draft and are in dire need of pitching this season.
In six outings and 12.1 IP, Cox is posting a 0.00 ERA, 2.13 FIP, and 3.68 xFIP, which are all solid marks. Cox is not just striking out 9.49 batters per nine innings, but he is also producing a 3.25 K/BB ratio, which would be his best mark in that category since 2019 when he produced a 3.25 K/BB ratio in High-A Wilmington.
The 26-year-old lefty has gotten off to a sensational start, despite not possessing elite velocity, as Josh Keiser of KC Sports Network mentioned on Twitter on Tuesday.
The Royals have struggled to fill the fifth spot in the rotation since Brad Keller went on the IL, as they have opted to use “openers” with bulk guys like Cox and Mike Mayers filling after the first or second, depending on how long the “opener” has gone. However, Cox’s success this season begs Royals fans to ask this two-part question, especially with the rotation spot still TBD for Wednesday’s contest against Cleveland:
Should the Royals move Cox to the rotation for that fifth spot? Or should Quatraro keep Cox in a bullpen role where he can be used as both a middle-inning and long reliever?
Let’s take a look at Cox’s success this year, and what Royals fans can expect from the surprising lefty in both the short and long-term.
Cox Succeeding With Three Good Pitches
When looking deeper into his overall metrics, there’s a lot to like about Cox this season. Not only are the ERA and FIP numbers low, but he is also producing a K rate of 31 percent, a CSW rate of 33.8 percent, and a swinging strike rate of 18.1 percent. Those numbers place him in the upper 86th, 88th, and 95th percentile of the league, respectively, according to Pitcher List.
Hence, it’s not a surprise that Nick Pollack, founder and head pitcher guru of Pitcher List, mentioned Cox would be the biggest sleeper performer from the Royals pitching staff in one of his “bold predictions” this morning.
After making his MLB debut last May, the Royals have seen Cox add more vertical movement on his four-seamer despite a slight drop in velocity.
Last month, his four-seamer averaged 92.8 MPH. This month? It’s only averaging 91.9 MPH, but as one can see in the chart below, the vertical movement on the pitch is considerably up in June thus far.
As a result, his whiff rate on the four-seamer has jumped from 25 percent in May to 48.6 percent in June. And this is despite having a much bigger sample in the month of June.
Cox’s ability to add more rise to his four-seamer has helped his ability to locate his four-seamer in optimum locations of the strike zone, which is up and on the edge or slightly above the zone.
When comparing his overall four-seam fastball heatmap, and his fastball heatmap on whiffs, it is easy to notice the correlation between the two graphs. That similar upward trend shows that Cox is commanding his primary pitch well, which explains why he is having such success against MLB hitters so far in his rookie campaign.
For the most part, Cox is avoiding the middle areas with his four-seamer, which is a big reason why opposing hitters haven’t been able to do too much damage against him just yet on the pitch. For the season, hitters are not just posting a .177 wOBA on the pitch, but also a .273 xwOBA and 36.4 percent hard-hit rate as well, according to Savant.
Here’s an example of Cox generating swinging strikes of the Angels’ Brandon Drury and the Rays’ Jose Siri on the four-seamer, despite variances of velocity on the respective fastballs.
The command makes a big difference on both pitches, even without premium velocity. The four-seamer against Drury is slower but is commanded in a tough area of the strike zone for Drury. As for the one against Siri, the extra velocity and vertical movement of the pitch causes Siri to chase out of the zone and strike out on a 2-2 pitch.
The four-seamer has been key to Cox’s success in 2023. However, he’s far from a one-trick pony on the mound.
Here’s a look at the run value metrics of his pitch arsenal this season. Notice that in addition to showcasing a robust pitch mix, he also has found tremendous success with two other pitches beyond his four-seamer.
The changeup has been his second-most utilized pitch at 21.3 percent, and hitters are producing a meager .100 wOBA on the offspeed offering this year so far. That being said, his curveball and cutter, which he throws 14.4 percent and 12.5 percent of the time, respectively, have been much more impressive pitches, especially on a whiff and K rate end. His curveball is producing a whiff rate of 44.4 percent and a K rate of 60 percent while his cutter is producing a whiff rate of 42.9 percent and a K rate of 33.3 percent.
Thus, the high whiff and K rates on those two pitches, as well as their decent usage rates for third and fourth pitches, demonstrate that Cox has options in his arsenal, even if (and most likely when) he sees regression on the four-seamer in terms of effectiveness in the future.
In fact, when looking at the whiff heatmaps of both curveball and cutter, it may make more sense for Cox to utilize those two pitches more, especially if he is moved to a spot in the Royals rotation soon.
Cox has succeeded with the curveball and cutter low in the zone, with the cutter having more success in the glove-side area while the curve has had more effectiveness in the arms-side area. Both pitches play well with the changeup, which typically is located more on the arm side edge of the strike zone, according to its pitch heatmap.
Despite that slight difference in the typical location of the pitches, the sharp cutter plays well with the looping curve thanks to their similar movement and Cox’s command of the pitch against opposing hitters, which can be seen in the clip compilation below.
Therefore, Cox doesn’t have the profile a typical LOOGY (left-handers batters only reliever) who solely relies on a couple of pitches to get through an inning or two in relief.
Rather, he has a diverse arsenal that could grow and become more effective, especially if Quatraro should give him opportunities to pitch four to six innings in a starting role.
Can Cox Handle a Lineup Multiple Times in a Game?
The Royals need help in the rotation, especially with the recent struggles of not just Singer but Zack Greinke, who has dipped a lot in June after being named Pitcher of the Month for the Royals in May.
That being said, does Cox have the ability to succeed in a starter’s role at the Major League level?
Cox at least has experience in the role, as the Omaha Storm Chasers primarily used him as a starter this season. According to his Baseball-Reference splits, he has made eight starts this year for the Storm Chasers and below is a look at how his eight starts compare to his eight relief appearances this year, both in Kansas City as well as Omaha.
On an ERA end, his starter numbers look just as good as his good as reliever metrics. His 2.92 ERA as a starter is better than his 3.06 ERA as a reliever.
On the other hand, all his other numbers look better on the reliever end of this table.
As a reliever, Cox has performed better in the areas of WHIP (1.076), K/9 (8.7), and K/BB ratio (2.83). That demonstrates that facing a lineup multiple times in a game could be a challenge for Cox at the Major League level, and that his gaudy stats so far could be due for some sharp regression if moved to the rotation.
Though he doesn’t have a a lot of data this year at the MLB level when it comes to him facing the batting order a second time around, his numbers are a bit more mixed in the limited sample, according to Fangraphs splits.
Amazingly, both of Cox’s hits have come when he’s faced a batting order a second time around. Thus, it’s not surprising that his wOBA (.354) numbers are much higher in this sample.
On the flip side though, five batters faced this season is hardly enough data to make a conclusion so far about his ability to pitch against a lineup multiple times in a single outing.
Will the Royals Test Cox Out as a Starter?
At this point, Cox ascending to a starting role makes sense, though I get the Royals lack lefty options out of the bullpen beyond Aroldis Chapman right now.
That said, Amir Garret is beginning a rehab assignment in Omaha, and he can provide that lefty relief option soon, which would give Quatraro another lefty to lean on out of the bullpen in addition to Chapman and Cox.
Furthermore, the Royals also have options like Brooks Kriske and James MaCarthur who can both provide single-inning or multiple-inning relief stints, depending on the situation.
Therefore, it makes sense for the Royals to give Cox a chance in the rotation, even if it may be a limited stint like Mayers’ short string of starts and “bulk-inning” outings this season. He certainly deserves it after a solid first six appearances at the Major League level this year.
Of course, there are those with reservations about Cox’s outlook, including Preston Farr of Royals Review, who has been covering the Royals’ farm system pretty diligently this season, especially those in Omaha.
Right now, it’s hard to exactly pinpoint what Cox’s exact projection will be at the Major League level, both for the remainder of this year and beyond. There certainly are some concerns from his starts in Omaha this year, but even then, he’s done a much better job this year with his command and “raiding the zone” in 2023 overall than he did in 2021 and 2022.
That kind of development may not exactly produce an “ace”, but it could result in a possible back-end starter or a hybrid guy who could rotate between the bullpen and rotation seamlessly depending on the situation.
When it comes to the latter, the Rays historically have flourished with guys with such profiles (Collin McHugh, Drew Rasmussen etc.), and it’s helped them weather through many key injuries to their rotation over the years.
It’s obvious Quatraro is keen on having that kind of depth and flexibility on the pitching staff, just judging by how he has used the fifth spot in the rotation so far this year…
And perhaps Cox could be that kind of success story, except in Kansas City rather than Tampa Bay.
Photo Credit: Jason Hanna/Kansas City Royals
Mr. O’B, thx for diving deep on Cox. Now that Angel Zerpa is rehabbing, how does his possible return to the big club factor in to how to use Cox?
I think Cox has a role regardless but this stint will determine whether he’s a starter or simply a middle innings guy. They lack lefty options now beyond Aroldis (and will lack that when he’s traded). Thus, if he doesn’t do well as a starter, the Royals can simply plug him back into the bullpen as they know he can be effective in that capacity.