Hatch is expected to sign a contract with the Nippon-Ham Fighters of Nippon Professional Baseball in Japan, Yakyu Cosmopolitan reports.
Pittsburgh optioned Hatch to Triple-A Indianapolis on Tuesday.
Hatch is listed as the Pirates' opening pitcher for Saturday's game against the Cardinals.
Hatch did not factor into the decision Monday, allowing two hits and one walk over three scoreless innings against St. Louis. He struck out one.
Hatch will join the Pirates on Tuesday, Jason Mackey of the Pittsburgh Post-Gazette reports.
Hatch was claimed off waivers by the Pirates on Sunday.
Hatch was designated for assignment by the Blue Jays on Friday.
Toronto recalled Hatch from Triple-A Buffalo on Wednesday, Shi Davidi of Sportsnet.ca reports.
The Blue Jays recalled Hatch from Triple-A Buffalo on Saturday, Keegan Matheson of MLB.com reports.
Hatch was optioned to Triple-A Buffalo on Friday, Mike Wilner of the Toronto Star reports.