The Twins signed Hartwig to a minor-league contract with an invitation to spring training Thursday, Darren Wolfson of Channel 5 Saint Paul reports.
Hartwig split the 2025 season between Triple-A Syracuse in the Mets organization and with the Hanshin Tigers of Nippon Professional Baseball in Japan. Slated to turn 28 later this month, Hartwig has collected a 5.14 ERA and 34:19 K:BB over 42 innings during his time at the big-league level.