Diamondbacks Top Prospects #28: RHP Conor Grammes

Grammes is another hard-throwing reliever with nasty stuff but has not found success in pro ball.

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Name: Conor Grammes

Age: 25

Position: Relief Pitcher

Acquired: 2019 Draft, 5th Round (152), $300K signing bonus

Tools: Fastball 65, Curveball 55, Slider 60, Command 30, Overall 40

Grammes has some very impressive stuff, but hasn't found a way to harness it yet in pro ball. When he's near the zone, he has three swing-and-miss pitches that can overwhelm hitters. His fastball sits 95-97 MPH but can reach back for triple digit velocity. Given the combination of three plus pitches and poor command, a move to short relief may be in order to see if he can overwhelm minor league hitters.

ETA: 2024

Risk: Very High

Top 30 List

2022 Overview

As a converted two-way player in college, the lack of reps had stalled Grammes' progress until he needed Tommy John surgery in July 2021. He returned with High-A Hillsboro and struggled to throw strikes. In 18 innings he struck out 33 and walked 13, posting an 8.50 ERA. The 37% strikeout rate was a big positive, which meant he was capable of putting away hitters with his stuff. 

2023 Outlook

Grammes is Rule 5 eligible, but the fact that he has only 60 professional innings under his belt and isn't 100% back from Tommy John surgery may allow him to go unclaimed. He'll likely start the 2023 season with High-A Hillsboro again just to show he's healthy and still striking out hitters at a high rate. The Diamondbacks will need to see if he can handle pitching every other day or even back-to-backs as he's further removed from the surgery, so they can project if he can pitch in the back-end of the bullpen. As he gets more comfortable on the mound and throwing more strikes, expect Arizona to aggressively promote him to Double-A and even Triple-A like with Justin Martinez. A good year will put him on the 40-man roster by the end of the calendar year.

MLB Projection

Grammes will be the most difficult projection on the list because his range of outcomes could be flaming out in High-A to becoming a shutdown reliever in the back-end of the Diamondbacks bullpen. The combination of swing-and-miss stuff and poor command makes him a candidate for short outings in relief.