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Re-Evaluating Diamondbacks Pitcher Development Pace

They haven’t been quite as slow as I’ve thought, but it’s time to promote Tommy Henry and Corbin Martin

Syndication: Arizona Republic
Tommy Henry pitches in spring training
Michael Chow/The Republic / USA TODAY NETWORK

Have the Diamondbacks been too slow to promote minor league pitchers within the system and to the major leagues ? I’ve made that criticism in the past, and I’m not alone in doing so. However recently I’ve been taking a closer look and realized my view on one or two players may have created some bias and skewed my overall evaluation. The impetus for this article was born out of the Druw Jones signing discussion thread but the thought process started before then. So let’s dive in !

Pitching Environments

First we need to acknowledge the difficulties the D-backs face in developing pitching. Three of their four minor league venues are hitters parks in hitters leagues. We’ve long since accepted the fact that Reno is a very difficult place to pitch. However Amarillo in AA, and Visalia in A, are also very good environments for hitters and difficult for pitchers. Amarillo in particular is borderline ridiculous. I covered this in some depth back in November of 2021 HERE. If you’re unfamiliar with these factors I’d suggest clicking that link and giving it a read.

A New Coach, A New System

It’s a well known fact that the Diamondbacks have had difficulty drafting and developing pitching over the years. The proof is the lack of home grown pitchers at the major league level. Full Stop.

Heading into 2022 the team hired Brent Strom and implemented a “new system” (for them) in which the assistant pitching coaches (Dan Carlson and Barry Enright) would rotate back and forth between majors and minors, working with the coaches and players throughout the organization to impart the methods and philosophies espoused by Strom. The intent of this was to allow them to accelerate the development of their minor league pitchers so they’re ready when they reach the majors to execute the game plan. You can read about this system HERE

They’ve only had 4-5 months to implement this. It probably takes a lot longer than that to establish a good system wide method for developing pitchers and have it bubble up to results in the upper minors and majors. Hopefully Strom sticks around for at least a couple more years. He really is a great coach in my opinion, regression at the major league level notwithstanding.

A Detailed Look at the Draft Classes

If one were to go back and look at the names from the 2017 Draft and the 2018 Draft it’s clear none of the pitchers from those drafts advanced well enough to be reliable MLB pitchers. They were just bad drafts for the club and they haven’t been able to make anything out of them.

What we’re really talking about here is the 2019 draft class. The class that got in minimal innings in 2019 before the cancellation of the 2020 minor league season.

Lets go name by name (Player names link to their game log and splits page for your easy reference) and see how they’re doing now and try to identify a pitcher they’ve moved unreasonably slow:

Blake Walston: Drafted out of high school, got 11 IP in 2019. In 2021 he made 19 starts, 8 in A ball, promoted, then got 11 starts in A+ and threw 95 innings, total 106 IP prior to 2022. After just 4 starts in A+ this year, he was promoted to Amarillo, where he has really struggled with the environment, 7.69 ERA, 1.887 WHIP

Verdict: Not promoted too slowly, but not progressing as hoped

Drey Jameson: Heading into 2022 he had 28 starts, 122 pro innings under his belt. Promoted to AA Amarillo to start 2022 he had 4 good starts, and then was promoted quickly to AAA Reno where he’s gotten crushed. In 13 games, 60 IP he has a 7.69 ERA, given up 71 hits including 13 homers, walked 27, for a 1.642 WHIP. He was hit especially hard July 1 & July 7.

Verdict: with just 200 professional innings, and doing poorly at AAA, he’s not been promoted too slowly and has not earned a MLB callup.

Ryne Nelson: Made 29 starts, 134 professional innings prior to 2022. They started him right off in AAA Reno this year, where he’s made 18 starts, and thrown 90 innings with a 5.72 ERA. His last 9 starts have been better though as he’s 5-1 with a 4.38 ERA

Verdict: Just 224 professional innings that are not outstanding, but in a tough environment recently stabilizing somewhat. Not promoted too slowly, but he’s almost ready.

Tommy Henry: Got into 3 games after being drafted in 2019, throwing 3 innings. In 2021 promoted straight to AA , 23 games, 115 IP. Went straight to AAA Reno to start 2022 and has been really good in 18 starts 3.55 ERA, IN RENO !

He did struggle with walks early on, issuing 29 free passes in 41 IP, but over his last 55 IP he’s walked just 11, struck out 56 and given up just 4 HR. Verdict: The team is about 2-3 weeks late in promoting him to MLB in my view.


Martin has been an enigma. Coming over in the Greinke trade he initially struggled to stay healthy and when given the opportunity in MLB pitched poorly save for a couple of decent relief outings. Sent down in May, he was up and down prior to his last two starts.

From May 10 thru July 2nd : 10 G, 46 IP, 6.46 ERA 21 BB, 48K, 8 HR

BUT, over his last two starts July 8 and July 14th he’s thrown 14 IP and given up just 1 run on 6 hits, 3 walks and 13 K’s. So maybe he’s found something. Prior to Martin’s turnaround the team turned to Tyler Gilbert earlier this month instead of Martin (or Henry), and he’s given them 3 pretty decent starts, giving up just 4 runs in 14.1 IP, despite all the usual hard contact. That said, Gilbert is not the future and it’s time to promote Martin again and find out once and for all if they have a starting pitcher there or not. If he fails this time, then they should convert him to short relief for 2023 and see if his stuff plays up in the pen.


The only minor league starter I can point to that probably should have been pitching in the majors prior to the All Star Break is Tommy Henry. Unfortunately they signed Dallas Keuchel in early June before it was clearly evident that Henry had turned around his command issues. Once they went down that road with Dallas they felt obligated to see it through. If it weren’t for Keuchel being here I’m pretty sure Henry would have gotten the call. I don’t believe Keuchel and his 9.64 D-backs ERA will be here too much longer, but Henry may need to wait a couple more weeks.

One Final Word on the 2020 draft class. Brandon Pfaadt needs to move up to Reno. He probably will once Henry and/or Martin get up to MLB. Slade Cecconi is almost ready for Reno but a little behind Pfaadt. Bryce Jarvis is having disastrous season. I’ll leave it at that.