Trent Thornton was optioned to Buffalo in a corresponding move.
White will make his debut for the Blue Jays as pitching coach Pete Walker confirmed on Friday.
The 27-year-old was acquired by the Blue Jays from the Los Angeles Dodgers along with Alex De Jesus in exchange for Nick Frasso and Moises Brito.
White is sporting a 1-2 record with a 3.70 ERA and 1.250 WHIP in 56 innings of work this season.
The Blue Jays needed a starter for Saturday after Ross Stripling was placed on the 15-day injured list with a glute/hip strain earlier this week.
White hasn’t pitched since July 26 when he gave up two runs on nine hits in six innings in a no-decision against the Washington Nationals.