Zac Thornton built a productive rookie season around changing speeds and pitch shapes, using a seven-pitch mix to give the Mets effective starts without an overpowering fastball. Improving his changeup is a priority heading into 2027.
The 24-year-old left-hander finished 2026 with a 3.42 ERA across 15 starts and 63 strikeouts in 84 1/3 innings, according to Jared Greenspan’s analysis for MLB.com. His fastball averaged 92.3 mph, placing him in the 18th percentile in the majors, while his 17.8% swing-and-miss rate was eighth lowest among 178 pitchers who threw at least 80 innings.
Thornton told MLB.com in August that keeping hitters from settling into a rhythm was central to his approach.
“Just giving them different looks every time,” Thornton said.
The cutter carries the workload
Thornton’s most frequent offering was an 89 mph cutter, which accounted for 31.7% of his pitches. Among starting pitchers who threw at least 1,000 pitches, only Ryan Johnson at 39%, Aaron Civale at 35.5% and Foster Griffin at 32.5% used a cutter more often. Drew Rasmussen followed Thornton at 28.9%.
The pitch was a regular option against hitters on either side of the plate. Thornton threw it 32% of the time against right-handers and 31% against left-handers, continuing an approach he developed in college.
Thornton said the Mets’ pitching and development staff encouraged him to keep using the cutter both inside and outside the strike zone. Greenspan noted that cutters have become increasingly common: 192 pitchers threw at least 100 in 2026, compared with 140 in 2021.
Slider and sweeper offer different options
Thornton used his slider about 8% of the time at an average of 84.7 mph. Although its movement overlaps with his cutter, the slower slider drops more, and he uses the two pitches in different locations.
“The sliders are going to be low on the plate, below the zone,” Thornton said. He explained that his cutters are intended for higher locations.
His sweeper provided another change of pace. Thrown about 16% of the time at 80 mph, it moved 12.8 inches toward his glove side. That horizontal movement offered a different look from the pronounced vertical movement associated with many of his other pitches and his high, 50-degree arm angle.
Thornton said the sweeper was particularly useful against left-handed hitters because it took them below the 85-92 mph range. Opponents batted .200 against it with a 24.7% swing-and-miss rate, his best results in those measures on any individual pitch in 2026.
Changeup development comes next
The changeup, averaging 84 mph and representing about 5% of Thornton’s pitches, is the offering he most wants to improve. He told MLB.com he has worked on it for years but has fewer repetitions with it than with his cutter and other pitches.
His arm angle produces a changeup without substantial drop or strong movement toward his arm side. Greenspan’s analysis emphasizes how that pitch works alongside a fastball, rather than judging its movement in isolation, citing Dylan Cease, Patrick Sandoval and Noah Cameron as examples of pitchers succeeding with unusual changeup profiles.
Thornton’s results came from a limited sample: He threw 58 changeups in 2026, with opponents going 6-for-17 and producing a 10.3% swing-and-miss rate. Developing the relationship between that pitch and his fastball gives him a specific area to address before his next season.
FingerLakes1.com is the region’s leading all-digital news publication. The company was founded in 1998 and has been keeping residents informed for more than two decades. Have a lead? Send it to news@fingerlakes1.com.