Pittsburgh Pirates: Three Pitchers to Watch in 2024 Based on Stuff+

Could these three pitchers surprise with the Pittsburgh Pirates this season?

Stuff+ is a new statistic aiming to measure how ‘nasty’ a pitch is. According to FanGraphs, it factors in multiple noteworthy elements of a pitch, such as its speed, spin rate, movement, and release point. Although it’s not a predictive statistic, one could use it as a tool to predict who could break out next season. Good stuff means there’s potential for more.

That’s exactly what I’m here to look at today. The Pittsburgh Pirates have a few pitchers who appeared in the Majors last year and registered high remarks per stuff+. Keep in mind that this is on a similar scale to something such as wRC+ or ERA+, where 100 is average, 101 is 1% better than average, and so on.

Hunter Stratton

Hunter Stratton was a former 16th-round draft pick who made his debut in 2023 and didn’t look bad when he arrived in the big leagues. Stratton’s primary pitch was his cutter, which he used about 50% of the time. The pitch is a low-90s offering but averaged out just a touch over 2700 RPM. Although his cutter had a slightly below-average drop, he had 5.8 inches of vertical break, the seventh-highest average vertical break among any cutter from any pitcher (min. 50 pitches). Stuff+ pinned his cutter at 109.

His best pitch per stuff+ was his four-seam fastball at 122. He threw this pitch around 96 MPH and approached 2600 RPM on average (2576 RPM, to be exact). Although Stratton’s fastball had good spin and speed, he didn’t take full advantage of either. His active spin rate on his four-seamer was just 73%, which caused his four-seamer to have below-average movement. Still, because of its velo, plus-plus spin rate, and lower release point, it plays up to a degree.

Stratton used his slider the least often in his brief big league debut and came out with a 113 stuff+. A mid-80s pitch, the righty reliever averaged 2759 RPM with the offering. Unlike with a four-seam fastball, the lower the active spin rate on a slider, the better, and Stratton averaged just 44%. This gave it 10.9 inches of horizontal break, which would have been top 30 had he pitched enough to qualify.

Although Stratton’s time in the Majors was brief, he pitched well in the 12 innings he tossed. Stratton only allowed three earned runs and just three walks to the 47 batters he faced. He may have only struck out ten, but he had a 51.5% ground ball rate.

After being designated for assignment by the Pirates in November, Stratton returned on a minor league contract in early December. Stratton will begin the season back at Triple-A Indianapolis, but could see time in the majors once again.

Jackson Wolf

The Pirates acquired left-handed pitching prospect Jackson Wolf last trade deadline. You wouldn’t think that a guy who averages 88-90 MPH would be on a list like this. Stratton and Selby are hard throwers. But in Jackson Wolf’s lone MLB start, he registered a stuff+ of 117. All three of the offerings he used registered as above average. That ranged from 107 at worst to 132 at best. That’s only 1% worse than David Bednar and 1% better than San Francisco flamethrower Camilo Doval.

Once you dig into some of his pitch metrics, you can kind of see why he is so highly regarded in the eyes of stuff+. He may only sit 88-90 MPH with 2108 RPM on his fastball, but with an active spin rate of 96%, he throws his four-seamer with above-average vertical and horizontal break. With 12.9 inches of horizontal movement, Wolf would have been among the top 20 fastballs had he thrown enough to qualify. Overall, Wolf’s fastball sat at 107 in stuff+.

Both his slider and changeup have slightly below-average movement, but they were even nastier per stuff+ than his fastball, which arguably had better qualities. However, that’s probably because of his release point. Wolf’s extension comes out to about seven and a half feet, making his velocity way up. The second reason is because of his side-arm-like arm slot, which sat around five feet. The lefty also had just a 2.91-foot horizontal release point. Wolf’s slider had a 120 stuff+ rate, while his change-up clocked in at 132.

Overall, Wolf pitched well in Double-A, working to a 4.13 ERA, 4.02 FIP, and 1.11 WHIP. He held opponents to a .226 batting average while striking them out at a 26.8% rate. His 1.23 HR/9 was slightly below average, but he also was great at limiting walks with a 6.4% walk rate. But there was one start where he allowed eight earned runs in just 3.1 innings. Outside of this one game, he had an ERA of just 3.65 while his WHIP would drop to 1.04, and both his strikeout and walk rate would move in the right direction to 27.7% and 6.2%, respectively. Wolf also struggled through his final four starts of the season. Going into August 30th, he had a 3.81 ERA, 3.73 FIP, and 1.05 WHIP with a strikeout rate approaching 30% (29.3%) and a sub-7% walk rate (6.6%).