The Diamondbacks will promote pitching prospect Drey Jameson before tomorrow’s game against the Padres, reports Nick Piecoro of the Arizona Republic. They’ll need to formally select his contract to do so, but the club already has a 40-man roster vacancy after designating Wilmer Difo for assignment this week.
It’s the first MLB call for Jameson, who has been one of the organization’s more interesting pitching prospects the past few years. A supplemental first-round pick (34th overall) out of Ball State in 2019, Jameson signed for $1.4MM. Credited with a mid-upper 90’s fastball and a promising combination of secondary offerings, the right-hander looked like a potential impact arm if he could develop more consistent control. Jameson didn’t get much of an opportunity until last year, with the 2020 minor league season wiped out by the pandemic. He posted excellent strikeout numbers with solid walk rates between High-A and Double-A last year, solidifying his status as one of the better arms in the system.
FanGraphs and Keith Law of the Athletic each slotted Jameson at the back half of their Top 100 overall prospects entering the season. Baseball America and Kiley McDaniel of ESPN each had him just outside the Top 100 but placed him among the ten most talented players in a strong Arizona system. Jameson dominated through four starts at Double-A to start the year, but he’s struggled to acclimate to the minors top level.
Since being promoted to Triple-A Reno at the beginning of May, the 25-year-old has made 22 appearances (21 starts). He’s surrendered a 6.95 ERA across 114 innings, striking out a personal-low 21.2% of opponents. Jameson’s 8.2% walk rate is manageable, but he’s allowed 1.66 home runs per nine innings and been plagued by a .351 batting average on balls in play. Reno is one of the more hitter-friendly environments in affiliated ball, which has certainly been a factor, but BA’s scouting report on Jameson also notes that hitters are able to identify the ball early in his delivery, causing his fastball to play below its velocity.
That’s something Jameson and pitching coach Brent Strom will work on, but it’s also easy to see the appeal with the 6’0″ hurler. Prospect evaluators suggest his slider is a plus-plus offering (a 70 on the 20-80 scale) at its best, and Jameson also shows an average or better changeup and curveball. Adding him to the 40-man roster at the end of the season to keep him from being selected in the Rule 5 draft was a no-brainer for the D-Backs’ front office, and they’ll take the season’s final few weeks to get an early look as Jameson tries to carve out a role on the 2023 staff.
Arizona is likely to see Zach Davies hit free agency this winter, thinning out their rotation depth. Zac Gallen has cemented himself as a top-of-the-rotation arm, and Merrill Kelly is amidst the best season of his career. Madison Bumgarner has been a fixture in the starting staff since signing an $85MM free agent deal heading into 2020, but his ERA is again approaching 5.00. The veteran may not be in imminent danger of losing his rotation spot, but Arizona has begun to introduce some of their younger starting pitching options at the big league level. Jameson joins Tommy Henry and Ryne Nelson as prospects to make their MLB debuts this season. Henry has struggled but Nelson (who ironically also broke in against the Padres a couple weeks back) hasn’t allowed a run with a 13:2 strikeout-to-walk ratio through his first two starts.