The first part of the preview focused on the consensus top prospects, this installment will focus on the sleepers. While a good farm system typically has more high end prospects, a good player development program will churn out players with underappreciated skill sets or smooth out the edges for high volatility prospects. In order to build a successful championship roster, you need to be able to turn out sleepers as reliable contributors.
Justin Martinez, RHP, Age 19, ETA: 2024
In terms of raw arsenal, Martinez is only bested by Frias, Martin, and Jarvis in the system. He utilizes a mid to upper 90s fastball that he’s still developing the command for. He complements that fastball with a tweener breaking ball (more slider than curve) and a change-up, both of which are projected to be at least average by Fangraphs. He has decent command of the slider, which he can locate around the low, glove-side corner of the plate. The change-up is very much a work in progress and will be a critical pitch for him to stick as a starter.
Compared to your typical high school arm from the 2019 Draft, Martinez compares pretty well. I would put him on a similar tier as former D-backs draft pick Brennan Malone in terms of arm strength and projected physical profile, which is probably why the team felt comfortable enough to move the latter for Starling Marte last offseason. Martinez is projected to fill out a 6’3” 180-lb. frame as he climbs up the system. He’s probably going to start 2021 in Extended Spring Training before getting a look at the short season levels, if they still exist.
Josh Green, RHP, Age 25, ETA: 2021
Green is probably the biggest sleeper in the system, pitching well in AA in just his first full season in the minors in 2019. He’s not going to blow guys away, but is a difficult pitcher to square up due to a heavy sinker in the low 90s and good secondary pitches. As a result, Green was able to force ground ball contact on 66% of balls put in play against him. He complements his pitch to contact style by limiting free passes, with a walk rate of only 4% in 2019. The combination of extreme ground ball contact and limit free passes should make him an effective innings-eater at the back-end of the rotation.
Green could be one of the first arms to pop up from the minors, with his likely assignment being AAA. He’s pretty much as ready as he’ll be for the majors.
Jeferson Espinal, OF, L/L, Age 18, ETA: 2024
Alek Thomas and Corbin Carroll rightfully take up a lot of praise for the current state of the farm system, but I’d be remiss to not include a Latin American player with similar skills lower down the list. The D-backs splurged on Alvin Guzman in the 2018 July 2nd signing class, but it’s been Espinal who has emerged from the class. Espinal is younger, but has a better physical profile than the 5’10” Carroll and 5’11” Thomas. However the tradeoff and reason he’s lower on most lists is he doesn’t have the batting eye and quality of contact skills the D-backs top outfield prospects can boast.
He’ll get his first look state-side in 2021, likely in Extended Spring Training before playing either in a rookie or some other short season league. Espinal has the speed and instincts to handle center field, but isn’t on the same level of defender as Carroll so he could end up in a corner if they’re both on the same roster. The biggest improvement he’ll need to make offensively is make adjustments to his swing path to tap into more of his above-average power.
Tristin English, 3B, R/R, Age 23, ETA: 2022
English is a classic corner infielder power bat, but completely crushed the Northwest League after getting drafted in the 3rd round. As a former pitcher, he has the arm and possibly the athleticism to handle 3B. In his half season sample, English put up a .290/.356/.482 slash (138 wRC+) with just an 11% strikeout and 6% walk rate as the level was far from challenging for him. It will be very interesting to see how his bat improves as a full time hitter instead of splitting time to refine his pitching skills as a former two-way player in college.
He likely starts the year with High A Hillsboro, but could finish the year in AAA. With Eduardo Escobar’s contract up after this season, English could be his long term replacement there.
Conor Grammes, RHP, Age 23, ETA: 2023
Grammes was a two way player at Xavier, but will be focusing on pitching in the pros. The stuff is electric as he features an upper 90s fastball and a plus breaking ball, but comes with the tradeoff of horrible command. In his summer debut, he had a 20/8 strikeout ratio in 15 innings. It’ll be interesting to see how he fares in a bullpen when facing tougher competition.
His best possible outcome is being a dominant single-inning reliever who relies on a north-south type game with his fastball and curve (think James Karinchak). He still has a long way to go, but could be the team’s next closer or get me out of this mess reliever in a few years.