3 Pittsburgh Pirates prospects primed for breakout seasons in 2025

The Pittsburgh Pirates’ farm system contains a lot of unproven prospects. Some have barely played any pro ball, and some are coming off their first full season of play. With so many prospects graduating over the last few seasons, Pirates’ top prospect lists mostly consist of potential these days.

Buried among all that uncertainty are a wide variety of potential breakout candidates. Each of these three prospects are in a great position to have a potential breakthrough season this summer.

3 Pittsburgh Pirates prospects with 2025 breakout potential

Khristan Curtis

Khristian Curtis was a late-round selection by the Bucs, as they took him in the 12th round of the 2023 draft. Although he was taken with just the 347th overall pick, Curtis was ranked as the 197th best prospect in the draft by MLB Pipeline and 126th best by Baseball America. He definitely showed some promise in his first minor league season in 2024.

Curtis pitched 75.1 innings for Bradenton, working to a 4.06 ERA, 4.84 FIP, and 1.34 WHIP. He struck out just over a quarter of his opponents, with a 25.4% K%, but paired that production with a mediocre 1.19 HR/9 rate and allowed walks to 12.2% of the opponents he faced. He also allowed an 87.2 MPH exit velocity and a 7.6% barrel rate on batted balls, both of which were below average.

For what it’s worth, Curtis had a rough start to the season and was injured for all of July. From May 25 onward, Curtis pitched 48.1 innings, pitching to a 3.00 ERA, 3.58 FIP, and 1.21 WHIP. While his 11.1% walk rate was still unimpressive, he struck out more batters (with a 27.8% K%) and only allowed home runs at an 0.56-per-9 innings ratio. It was not a large sample size, but he performed well in it nonetheless.

Curtis has a myriad of pitches at his disposal. He tossed six different offerings at least 5% of the time in 2024. His most used pitch was his four-seam fastball, which sat in the mid-90s, topping out at 98. It’s an above-average pitch with great vertical movement. Curtis’ most-used secondary was a mid-80s slider that induced a whiff rate of 47.9%, which was about 10% better than average. It represents another pitch in Curtis’ arsenal that has above-average potential.

Curtis also mixed in a low-90s cutter that also induced a ton of swings-and-misses, with a 46.9% whiff percentage. His most prominent breaking pitch is an upper-70s curveball with over 50 inches of downward movement on average. Curtis’ go-to offspeed pitch is a mid-80s changeup with great arm-side movement that Baseball America projects to be another above-average pitch. He rounds his pitch mix off with a mid-90s two-seamer, though he only used this pitch 5.3% of the time.

Curtis stands at 6’5”, 210 pounds. He’s built like a starting pitcher with an arsenal that can play in a rotation. Having control of six different pitches can keep batters off balance, especially if he can improve his control. We’ll see how he does in 2025, but his strong end to the 2024 season and his promising array of offerings set him up nicely for next season.

Zander Mueth

The Pirates took many pitchers in the 2023 draft. In addition to Curtis, they also selected Zander Mueth early. Mueth was a high school pick who the Bucs selected 67th overall with their second-round competitive balance pick. Mueth has one of the highest ceilings among all Pirates pitching prospects, and will get his first extended look in 2025.

Mueth pitched 74 innings between the Florida Complex League and A-Ball in 2024, working to a 2.31 ERA and 1.31 WHIP, but a poor 4.59 FIP. The young right-hander struck out 23.8% of opponents faced and rarely allowed home runs. He allowed just two long balls, including none while with Bradenton. Granted, he induced just a 90.5 MPH exit velocity and 7.7% barrel rate, both of which were below average. Mueth was also very prone to walks, allowing 15.1% of opponents to reach via free pass.

Mueth uses three pitches on the mound. His sinker sits 93-94 MPH, topping out at 97 MPH at Bradenton. Baseball America pins it as a 60-grade pitch. He only has one breaking pitch, that being a slider, a second offering in his arsenal that BA grades out as a plus offering. Finally, there’s his mid-80s change-up. Although it’s behind both his sinker and slider, it is still an offering that has average potential.

There's a good chance that Mueth’s stuff could play up to an even higher level because of his deceptiveness. His release point extension was measured at 7.1 feet. For reference, Bailey Falter was in the 98th percentile of release point extension in the Major Leagues in 2024 at 7.3 feet. This makes his stuff look faster out of the hand. A 95 MPH fastball will look more like a 96 MPH fastball to the batter. Mueth’s arm angle is also very low at just 4.67 feet. For a Major League comparison, look at former All-Star closer Alexis Diaz or former Pirates pitcher Rich Hill.

Mueth’s 2024 season had its ups and downs, but there’s still a ton of promise here. He stands at 6’6”, 205 pounds at just 19 years old. He does not turn 20 until late June. With his mix of youth, stuff, and deception, Mueth has a chance to be one of the Pirates’ best prospects within the coming years, and is someone to watch potentially break out in 2025.

Omar Alfonzo

Omar Alfonzo played his first full minor league season in 2024. The catcher/first base prospect spent most of his previous seasons in the Florida Complex League, appearing in 52 games for Bradenton in 2023, but 2024 was his first season appearing in at least 100 games with more than 300 plate appearances. What he showed off was very promising.

Alfonzo spent most of the season at Bradenton, where he hit .247/.353/.388 with a .356 wOBA and 115 wRC+ in 354 plate appearances. He only had five homers and a .135 isolated slugging percentage and struck out 26% of the time, but he walked in 12.7% of his plate appearances and had some above-average numbers under the hood. Alfonzo’s whiff rate of 26.3% and his barrel percentage of 5.2% were both slightly better than average, but he displayed a ton of raw power. His 92.8 MPH exit velocity was the best among all players at A-Ball, with at least 250 plate appearances, by a mile. The next closest was Miami Marlins’ minor-leaguer Ryan Ignoffo at 90.1 MPH.

Alfonzo’s solid numbers at Bradenton earned him a late-season promotion to Greensboro. He only received 97 plate appearances before the season ended, but he did well in the small sample size, batting .247/.371/.457. He hit five home runs with a .210 isolated slugging percentage, and while he kept up a 25.8% K%, he also walked 16.5% of the time. 

Baseball America ranked Alfonzo as the Pirates’ 18th-best prospect in their Prospect Handbook. MLB Pipeline has him as the Pirates’ 24th-best prospect. Both praise his patience at the plate, and both project him to have an average hit tool. With his raw power, he could hit for a fair amount of pop as well. BA also notes he improved his launch angle and saw his fly ball rate rise above 30% at Greensboro. Defensively, Alfonzo has a strong arm that will play behind the dish. He’s improved his receiving skills, and is praised for his internal work with pitchers.

Alfonzo’s raw power could make him a potential 20-homer catcher. If he continues to improve behind the dish, he’ll grade out solidly there, too. Alfonzo was able to reach High-A in just his age-20 season. He won’t turn 22 until early August. There’s a very good chance he reaches Double-A before the end of the ‘25 season, especially if he continues to hit like he did late last season for Greensboro.