D-backs' Reliever Prospect Kyle Amendt Has Been Dominant in Triple-A

Right-hander Kyle Amendt has emerged as one of the Diamondbacks' top relief pitcher prospects. In his 15 appearances with Triple-A Reno, he has pitched to a 1.00 ERA with 24 strikeouts and eight walks in 18 innings.

Going beyond just the ERA, Amendt is doing an excellent job at limiting runs in one of the toughest pitching environments in the minors. His FIP sits at 2.44 and xFIP at 3.63, in a league that averages 5.42 runs per game, and the average pitcher has a 5.07 ERA.

Amendt doesn't have premium velocity on his four-seam fastball, which averages just 91.6 MPH, but it plays up due to its unique shape. The pitch averages 16.3 inches of induced vertical break and 0.8 inches of glove-side break. To describe how unique the horizontal break is, there are only five pitchers in the major leagues whose average fastball breaks glove side (min. 250 pitches thrown): Brent Suter, Sonny Gray, Pete Fairbanks, Max Fried, and Porter Hodge.

Due to its atypical movement profile, Pacific Coast League hitters have struggled to hit Amendt's four-seamer. Opposing hitters are batting just .154, slugging .192, and have a whiff rate of 36.8%. Even though it's only coming in at 91.6 MPH, the results suggest that it could play at the major league level due to its unique profile and Amendt's over-the-top arm slot.

Just like his fastball, the curveball also capitalizes on a unique movement profile to baffle hitters. Most curveballs will typically break to the pitcher's glove side, but Amendt's breaks 0.4 inches to the arm side. The results have been excellent, as batters are hitting only .188 while slugging .250. His whiff rate on the pitch is 44.4%.

The slider has been the hardest-hit pitch, as it features the least unique pitch shape of his arsenal. Hitters are batting .333 with a .389 slug and 26.5% whiff rate. He uses that pitch almost exclusively to right-handed hitters, where the 4.6 inches of glove-side break can theoretically work away from their bats.

With the Diamondbacks trying to find solutions for their bullpen, Amendt has been knocking on the door for a promotion. With Monday's roster moves, they have two open spots on their 40-man roster if they want to bring him up. Juan Morillo or Joe Mantiply could be sent down to Reno to make room on the active roster.

However, due to the moving parts with the bullpen, it may not simply be Amendt's turn. Kendall Graveman has just been activated from the injured list after missing the first six weeks of the season, and Justin Martinez may not be on the IL much longer himself. Given the fluid situation of the bullpen, there's a good chance he'll get his first opportunity later this season.

During the Arizona Fall League last October Amendt spoke about growing up in Iowa and mimicking Adam Wainwright when trying to develop a curveball.

Diamondbacks Prospect Kyle Amendt Hones Stuff in Fall League

Other Notable Prospect Notes

Junior Sanchez (Visalia) and Hayden Durke (Hillsboro) were named their respective league's Pitcher of the Week. Sanchez pitched six scoreless innings, allowing two hits, one walk, and struck out eight against Rancho Cucamonga.

Durke pitched three innings of perfect baseball across two appearances, striking out six. Durke has a 1.13 ERA and a 50% strikeout rate with Hillsboro. He's holding opposing hitters to a .061/.233/.082 slash. The only real concern is that he occasionally will lose the strike zone at times, especially with his secondary stuff. Seven of his 11 appearances have gone without a walk, but he has a total of nine walks in the other four.

Slade Caldwell and Ryan Waldschmidt were recently added to MLB's Top 100 prospects list in their latest update. Caldwell slots in at the No. 99 spot and Waldschmidt at No. 100. Both players have gotten off to hot starts in their first full year in the Diamondbacks organization. Demetrio Crisantes, who opened the year as the No. 2 prospect in the organization, slid down to the fourth spot.

Speaking of Crisantes, the right-handed hitting infielder reached base in all six games played in the previous week. He hit .318 with two home runs, 10 RBI, and a 1.059 OPS. He stole three bases in four attempts. Crisantes has been the second-best hitter in Hillsboro behind Waldschmidt in OPS.

Kristian Robinson turned in a pretty solid week with Amarillo. He hit .286 with two home runs, five RBI, and more walks (6) than strikeouts (3). As mentioned in Monday's minor league recap, Robinson has shown significant improvement at the plate to start the 2025 season.