Gsellman signed a minor-league contract with the Nationals on Wednesday, Jon Heyman of the New York Post reports.
Gsellman left affiliated ball in 2022 to pursue a career overseas in Japan, where he recorded a 4.32 ERA and 1.52 WHIP across 139.2 total innings. The 30-year-old righty will likely head to Triple-A Rochester and serve as organizational depth as he attempts to work his way back to the majors.