Bailey signed a minor-league contract with the Athletics on Tuesday.
The Twins released Bailey on Saturday.
Bailey was designated for assignment by the Twins on Friday.
Bailey (biceps) was activated from the 45-day injured list Tuesday, Brandon Warne of ZoneCoverage.com reports.
Bailey (biceps) was transferred to the 45-day injured list Saturday, Aaron Gleeman of The Athletic reports.
Bailey (biceps) played catch Wednesday, Do-Hyoung Park of MLB.com reports.
Manager Rocco Baldelli said Friday that Bailey (biceps) still hasn't resumed throwing, Betsy Helfand of the St. Paul Pioneer Press reports.
The Twins placed Bailey on the injured list Sunday with right biceps tendinitis, Aaron Gleeman of The Athletic reports.
Bailey is scheduled to start Monday's game against the Pirates, Dan Hayes of The Athletic reports.
Bailey (1-0) allowed two runs on four hits and two walks over five innings Tuesday to pick up the win as the Twins downed the Cardinals 6-3. He struck out four.