Toronto traded the right-hander to the Kansas City Royals in exchange for minor-league righty Denis Samudio and cash considerations, the teams announced on Monday.
Seabold, who was designated for assignment by the Blue Jays after spring training but reacquired in a trade with the Detroit Tigers in May, appeared in five games with Toronto, allowing three earned runs over 3.1 innings.
His results were better over 11 appearances with the Tigers, with whom he posted a 3.45 ERA across 15.2 frames.
Samudio, 21, has appeared in six games across two levels of the low minors, recording a 4.12 ERA with 22 strikeouts and a .183 opponents batting average over 19.2 innings.
The Panama native joined the Royals as an international free agent last year.
Toronto had a need for roster space ahead of the expected upcoming returns of right-handed reliever Yimi Garcia and starter Shane Bieber.