The Pittsburgh Pirates have already debuted plenty of notable names this year. Brandan Bidois, Tyler Callihan, Esmerlyn Valdez, Jack Brannigan, Wilber Dotel, and Antwone Kelly have all played their first MLB game with the Bucs this year. They also recently called up pitcher Khristian Curtis for his MLB debut. There is still plenty of season left past the All-Star break, so who are some other prospects we could see the Pirates call up before the end of the year?
Connor Wietgrefe
Connor Wietgrefe recently earned a promotion to Triple-A after excelling at Double-A Altoona. His first 66.2 innings at the Curve yielded a 3.51 ERA, 3.42 FIP, and 1.27 WHIP. He struck out nearly a quarter of batters faced with a 24.6% K%, and walked 8.9% of opponents. The lefty also had a 0.54 HR/9 ratio, allowing just four home runs prior to his promotion. Wietgrefe was impressive over his last six Double-A outings, owning a 2.59 ERA, 32.3% K%, and 6.5% BB%.
Wietgrefe’s first four starts for Indianapolis have been a mixed bag. His first two starts saw him allow nine earned runs on 14 hits and five home runs over a dozen innings pitched. However, his last two outings have seen him tally 13 innings, allow just one earned run, only six hits, and only one of those hits leave the park.
Wietgrefe does not have overpowering stuff. He sits just 90-92 MPH with his four-seamer, as does his two-seamer. However, for what he lacks in overall stuff, he makes up for it in control and arsenal. Along with his four- and two-seamers, he also throws a cutter, curveball, slider, and change-up. He has displayed above-average command over all his arsenal, and throws from a low three-quarters arm slot. If Wietgrefe continues to pitch as well as he has for most of this year, it will be hard to deny him a call-up later this season.
Derek Diamond
The Pirates drafted Derek Diamond in the sixth round of the 2022 draft. Diamond started his pro career as a starter in the minor leagues, but transitioned to the bullpen nearly full-time in 2025. The right-hander opened 2026 on the injured list, but is now back in action and is posting some solid results.
Diamond has logged 30 innings between four levels of the minor leagues. In that time, he has a 3.30 ERA, 3.70 FIP, and a 1.13 WHIP. He has struck out 22% of batters while only allowing free passes at a 2.4% rate. His walk rate is currently the second lowest of any minor league pitcher who has thrown at least 30 frames this season. That low BB% has also helped him post a 19.5% K-BB%.
Diamond’s primary pitch is a mid-90s four-seam fastball with above-average movement. His primary breaking pitch is a mid-80s slider. Along with his fastball and slider, he’ll also occasionally mix in an upper-70s curveball, low-90s sinker, and mid-80s change-up. Plus, he has nearly seven feet of extension off the mound, making his velocity play up even more. With how much the Pirates’ bullpen has struggled this year, Diamond may be the next man up as the Pirates attempt to find some stability among their relievers.
Murf Gray
Murf Gray has exceeded nearly all expectations this year. The Pirates’ second-round competitive balance pick from last year has done nothing but rake at every level of the minor leagues this season. He is rocketing through the minor leagues at breakneck pace, and after starting the year at A-Ball Bradenton, is now at Double-A Altoona.
Gray is batting .325/.408/.607 with a .444 wOBA and 155 wRC+ over his first 376 plate appearances as a pro ball player. He already has 24 home runs on the season, with a .282 isolated slugging percentage. Gray has walked at a 10.6% pace and has a K% of just 19.6%. His contact rate is approaching 80% this year at 78.4%. The third baseman has made a great first impression since reaching Altoona. It’s only been three games and 13 plate appearances, but he already has two hits, including a home run, three walks, and only two strikeouts.
Gray is currently one of only ten minor league batters with an OPS over 1.000 in at least 300 plate appearances. He also has the tenth-best wOBA and wRC+. Only two Pirates prospects have hit at least 25 home runs since 2006, and Gray is just one more long ball away from reaching that milestone. Some may compare Gray to Konnor Griffin, given how quickly Griffin went from the minor leagues to his MLB debut, but Gray is even ahead of Griffin’s curve. Gray is slightly older, given he was a college draft pick (taken out of Fresno State), and reached Double-A sooner than Griffin did. It might not be a massive stretch to say Gray has a chance to make his MLB debut by the end of 2026.
