Left-hander Matt Gage has been reassigned to triple-A Buffalo in a corresponding move ahead of the series opener in Oakland.
The Blue Jays acquired Banda from the Pittsburgh Pirates for cash considerations on Saturday.
The 28-year-old has a 6.41 ERA in 19.2 innings over 23 games with the Pirates this season. He was designated for assignment by Pittsburgh last season.
You can watch the Blue Jays game against the A's — featuring Matt Chapman's return to Oakland — on Sportsnet and SN NOW beginning at 9:07 p.m. ET/ 6:07 p.m. PT.