Roark was released by Atlanta on Sunday, David O'Brien of The Athletic reports.
Roark was optioned to Triple-A Gwinnett on Sunday.
Roark had his contract selected by Atlanta on Thursday, Mark Bowman of MLB.com reports.
Roark agreed Monday with Atlanta on a minor-league contract, Mark Feinsand of MLB.com reports.
Roark became a free agent Wednesday after clearing waivers.
Roark was designated for assignment Friday
Roark was placed on the Family Medical Emergency List on Friday.
Blue Jays manager Charlie Montoyo said Sunday that Roark will be moved to a long-relief role, Arden Zwelling of Sportsnet.ca reports.
Roark won't make his scheduled start Sunday after the Blue Jays' game against the Angels was postponed due to inclement weather in Dunedin, Fla.
Roark posted an 8.44 ERA and 14:3 K:BB through 10.2 Grapefruit League innings this spring.