High Strikeout Pitchers in the System

But anyway, this isn’t about which light hitting outfielder the Diamondbacks should have traded. It is about the overlooked player the Diamondbacks got for McCarthy.

Josh Grosz was an 11th round selection of the Yankees in 2023, five picks after the Mariners drafted Brandyn Garcia. With the Diamondbacks’ own pick of Casey Anderson, he is the third member of the 11th round in 2023 in the organization. (That 2023 draft is looking pretty solid this year. Anderson seems to be finding his feet as a reliever in AA, Philip Abner has already reached the major leagues, and Tommy Troy and LuJames Groover are both knocking on the door. Caden Grice is finally healthy, and Jack Hurley looked to be turning things around at AAA.) These are just interesting facts that have no bearing on the discussion, which is the return for McCarthy.

Grosz starred at East Carolina, a “mid-major” school but one with a top-level (but extremely snake bitten) baseball program. They hold the record for most NCAA tournament appearances without ever making to Omaha, and only two teams are even halfway to their 35: South Alabama (alma mater of Turner Ward, Matt Peacock, and some guy named Luis Gonzalez) with 28, and Stetson. He entered the starting rotation in 2022 and started the game that looked to break the schneid. He gave up two runs (one earned) and the Pirates built a 7-2 lead in the seventh inning. But Texas came back to win and dominated the following day. He was a regular in a rotation that included Trey Yesavage in 2023, with mixed results. (East Carolina has produced some excellent pitching in recent years. In addition to Yesavage, Carson Whisenhunt and Gavin Williams both starred in Greenville post-COVID.)

He signed with the Yankees and got good results, performing well enough to get a spot start in AA. He was even better in 2025, but struggled after being traded to the Rockies in the Ryan McMahon deal. He was a bit unlucky; his xFIP- was 100, indicating that he would have been expected to get average results rather than the poor results he got.

The raw numbers of a 4.12 ERA and a 1.322 WHIP at Amarillo make it look like his luck has turned. That’s not accurate. Jose Cabrera leads the Soddies in WHIP at 0.862. His xFIP- is 75. Jonatan Bernal leads the Soddies in ERA at 1.32. His xFIP- is 63. Grosz’s xFIP- of 55 is closer to Kade Anderson’s than Cabrera’s. Kade Anderson was in line to be the top pick in the draft last year and has an ERA of 0.60 and a WHIP of 0.667 as a starting pitcher in the Texas League. His xFIP- is 46. (Lower numbers are better for minus stats, while higher numbers are better for plus stats, but the meaning is basically the same, with 100 average.) Grosz is allowing a .395 BABIP, which is substantially above his career numbers and is certain to come down. (All statistics are through Sunday, May 10.)

Since it’s not luck, how has he improved so much? It basically comes down to two stats which xFIP absolutely loves. He’s striking out more batters and getting more ground balls. And not by a small margin. He’s faced enough batters for his strikeout rate to mean something, and he’s striking out 40% of the batters he faces. In addition to the strikeout rate, he’s getting more than twice as many ground balls as fly balls.

It is imperative to note what I am not saying here. I am not saying that Josh Grosz is a future ace, or even a guaranteed future rotation piece. Strikeout rate is the only statistic that is really meaningful at this point, and players with strikeout rates like his tend to already be or eventually become relievers. I am not even saying that Josh Grosz would have success in the big leagues. But I do think he’s cracked the code to be a successful pitcher at Amarillo and Reno, if he can keep it up. Strike out batters, make the others hit the ball on the ground, and you can get good results, even at Hodgetown.

Grosz isn’t getting quite as many whiffs as one might like, but he’s still quite good in that department. He’s getting swinging strikes on 14.2% of pitches. For context, Seth Hernandez has the highest rate in the minors at 25%, Rio Britton has the highest rate in the organization at 18.1% (which is in the top-20 across the minors), Mason Miller has the highest in the majors at 26.5% (minimum 10 innings pitched) and Juan Morillo has the best in the organization at 16.1%. One would expect that to drop moving up levels, but it doesn’t always; Morillo is getting more whiffs in the big leagues than he did at AA.

Grosz’s ceiling is mid-rotation starter, and will most likely wind up as a reliever. We’ll likely never know if he would have been the return for a theoretical Thomas trade, but there’s a very good chance that the Diamondbacks wind up on the better side of the McCarthy trade in the end.

Here are the other pitchers who have faced 70 batters and struck out more than 30%. Sanchez and Aracena are the only other ones starting some of the time, and Aracena has also appeared in relief.

It’s interesting that none of these were signed as highly regarded prospects. The Diamondbacks signed Mercado last year after he went undrafted out of Oregon in 2024; he initially didn’t find any takers among the thirty big league organizations and signed with Idaho Falls in the Pioneer League. Rio Britton also attended Oregon once upon a time, but transferred to NC State and went undrafted. The Diamondbacks pounced quickly in his case and signed him in 2023. Aracena may be a prospect now, but he signed for just $70,000, while Sanchez and Santana do not have listed signing bonuses, meaning that they were almost certainly below $50,000. While there have been plenty of complaints (including from me) about the organizational failures in pitching development, there are a few success stories as well, but mostly on the bullpen side.

Jose Cabrera may be having the best season of any of the pitching prospects thus far, but he just missed the 30% cut. Brian Curley and Chung-Hsiang Huang are two starting prospects who have done well to keep walks down while striking people out in the 25-30% range. And pitchers in the complex haven’t faced enough batters yet to form any judgment. Dean Livingston had a solid debut, and Modesto Vargas can be added to the list of potential future bullpen arms who can reach triple digits, but it’ll be at least a few weeks before much more can be said.