Mets call up Zach Thornton to fill rotation hole against Nationals

The Mets are betting on strike-throwing over experience, and that makes Zach Thornton’s jump to Washington one of the more revealing decisions of their early-season rotation scramble. The 24-year-old left-hander will be promoted to pitch Wednesday against the Nationals, moving from just two Triple-A starts straight into a bulk role as the club tries to cover for Clay Holmes, who fractured his right fibula on a comebacker and landed on the 15-day injured list.

Carlos Mendoza said Holmes will be out “for a long time,” a blunt timeline that pushed the Mets toward Thornton instead of the more advanced options sitting in the system. New York considered Jonah Tong and Jack Wenninger, but chose the pitcher who had been in Syracuse for only two weeks. Mendoza’s assessment was simple: “He earned it.”

Thornton’s brief run at Triple-A showed why the organization was willing to make the call. He threw six solid innings in his Syracuse debut, then followed it with a career-high nine strikeouts over six scoreless innings on May 15. Across seven starts split between Syracuse and Double-A Binghamton, Thornton went 1-3 with a 3.16 ERA, numbers that suggest the Mets see a pitcher whose polish matters as much as raw stuff.

That profile is built around command. Thornton, a fifth-round pick in 2023, signed for $350,000 and has climbed from a modest draft slot into a real major league option by locating a low-90s fastball and leaning on a mid-80s slider. MLB Pipeline called him a polished strike-thrower with a bulldog mentality, and the numbers back that up: he posted a 4.0 percent walk rate in 2025, sixth-lowest among 691 minor leaguers with at least 70 innings. His 2025 surge, a 1.98 ERA with 78 strikeouts and 11 walks in 72 2/3 innings across High-A and Double-A, was interrupted in late June by an oblique injury.

The Mets are asking Thornton to do more than just survive. He is expected to work in a bulk role against Washington, either starting the game or following an opener, and the assignment immediately tests how far his command-first profile can carry him. Tong has a 5.68 ERA at Syracuse, while Wenninger has a 1.51 ERA but still drew concern over his command. By choosing Thornton, the Mets signaled that a rotation under strain will lean on precision, not power, as it absorbs another injury hit.