The Mets non-tendered Hartwig on Friday, Tim Healey of Newsday reports.
Hartwig spent most of 2024 in Triple-A Syracuse, though appeared in four major-league games for the Mets and posted a 6.75 ERA and 1.50 WHIP over 6.2 innings. He tore the meniscus in his left knee in mid-June, but he was able to return to minor-league action in early August. The 26-year-old will look to sign with a team who will give him a chance to compete for a bullpen spot during spring training.