It didn’t take long for New York Mets catcher Hayden Senger to realize Nolan McLean had a FastPass to the big leagues. The two were teammates in Syracuse when McLean made his Triple-A debut in May and Senger caught him for the first time. McLean’s sweeper swept better than any Senger had ever seen.
“It’s pretty insane,” Senger said recently, with a laugh. Three months later, with Senger again behind the plate, McLean held the Philadelphia Phillies scoreless over eight innings in his third career major-league start. McLean featured six different offerings but threw his sweeper the most — 28 of them, inducing three whiffs and 10 called strikes. He sliced through a potent postseason-bound lineup with just 95 pitches. Citi Field was electrified.
The sold-out ballpark was buzzing again two days later when Jonah Tong, arguably the best pitcher in the minors this season, joined McLean in the Mets’ rotation to limit the Miami Marlins to one earned run over five innings. And on Sunday, Brandon Sproat joined the festivities, taking scuffling veteran Kodai Senga’s turn in the rotation in Cincinnati and becoming the Mets’ third heralded pitching prospect in less than a month to make his MLB debut. Sproat held the Reds hitless through 5⅓ innings, but gave up three runs over six innings and ultimately took the loss in a 3-2 defeat.
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In David Stearns’ perfect world, the trio would have arrived with soft landings sometime next season. But the president of baseball operations decided the Mets, a playoff contender desperate for quality starting pitching with too many veterans either injured or struggling, needed them now.
“I think, as you go into the last month of the season,” Stearns said, “you want to have the best roster you possibly can.”
The three right-handers traveled distinct paths to opportunities in the middle of a postseason race. McLean, a former quarterback, was a two-sport and two-way player at Oklahoma State. Tong was a slight Canadian high schooler with a funky delivery. Sproat flashed high-ceiling tools in the SEC for the Florida Gators. Together, they highlight a booming farm system evaluators say is teeming with talent under Stearns’ watch.
Entering the season, Sproat, 24, was considered the best of the three. ESPN’s Kiley McDaniel ranked Sproat, a second-round pick in 2023, as the No. 62 prospect in baseball, while McLean was No. 123 and Tong was No. 147. But Sproat struggled early this season, pitching to a 6.69 ERA in nine starts for Syracuse through May 20. He rebounded with a 3.19 ERA over his next 17 outings behind increased velocity and movement on his 97-mph four-seam fastball.
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“Sproat has the best arm talent and the highest upside [of the three],” a rival scout said. “The ceiling with him is very high.”
But Sproat’s pitchability, according to talent evaluators, isn’t on McLean and Tong’s level, which helped McLean and Tong hurdle him to the big leagues.
“McLean and Tong are both extremely good pitchers, but neither has dealt with failure at the pro level,” a talent evaluator said. “And I’m going to be really curious how they handle that and how they can adapt both in their pitching approach and mentality. Sproat struggled a bit earlier this year, so he likely built up some kind of resilience and adaptability.”
The 24-year-old McLean’s development accelerated once he ditched hitting during summer 2024, his first full pro season. Focusing solely on pitching, the 2023 third-round pick optimized his unique ability to spin the baseball and climbed from Double-A Binghamton to Queens in 2025 while surging to No. 19 in McDaniel’s latest top 100 prospects ranking. Through four starts, McLean’s curveball has the highest average spin rate in the majors, and his frisbee sweeper ranks near the top. More importantly, he has issued just seven walks over 26⅓ innings after averaging four walks per nine innings in the minors.
“Despite the lack of pitching experience and being a two-way guy, McLean was always the safest [bet],” the rival scout said.
Tong, 22, was so far down the Mets’ 2025 organizational depth chart that he wasn’t invited to major league camp in spring training. A seventh-round selection in 2022 with a smaller frame and a drastic over-the-top delivery that resembles two-time National League Cy Young winner Tim Lincecum, Tong produces the highest arm angle of any pitcher in the majors this season.
With those unusual mechanics, he weaponized a 12-6 curveball, a changeup he added this season and an explosive fastball that features elite induced vertical break to dominate minor league hitters this season. He posted a 1.43 ERA across 22 Double-A and Triple-A starts, climbing to No. 21 in McDaniel’s latest prospect rankings and rocketing his way to the majors.
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“He’s a real development win for the Mets,” a rival executive said.
Development wins don’t count in the standings, though, and World Series trophies aren’t handed out for farm system rankings. The Mets would have preferred not relying on three rookies in September. But a starting rotation without a proven ace — Stearns opted not to acquire a premier pitcher over the offseason or before the trade deadline — has been plagued by injuries and underperformance throughout the summer.
Senga, one of the Mets’ projected top two starters this season, missed a month with a strained hamstring and stumbled so badly upon his return that he accepted a demotion to Triple-A on Friday to rectify his troubles. Sean Manaea, the Mets’ other projected frontline starter, has a 5.60 ERA in 10 outings after missing more than three months with a strained oblique. Tylor Megill landed on the injured list with a sprained right elbow in mid-June. Griffin Canning ruptured his left Achilles less than two weeks later. Frankie Montas — given a two-year, $34 million contract during the offseason — recorded a 6.68 ERA in seven starts before going to the bullpen and tearing the ulnar collateral ligament in his right elbow.
By mid-August, the Mets were dipping into their prospect bank for help. Come October, a club with championship aspirations and the second-most expensive roster in the sport could end up counting on the three youngsters to help them win games that matter — much sooner than they expected.
“I’m going to keep saying it,” Mets manager Carlos Mendoza said. “We’re going with what we feel are our best guys, day in and day out.”