Castro (elbow) signed a minor-league contract with the Astros on Nov. 18.
The Tigers released Castro (elbow) on Wednesday, Evan Woodbery of MLive.com reports.
The Tigers announced Wednesday that Castro recently underwent Tommy John surgery to address a right elbow sprain, Evan Woodbery of MLive.com reports.
The Tigers reassigned Castro to minor-league camp Monday, Jason Beck of MLB.com reports.
Castro signed a minor-league contract with the Tigers on Dec. 12.
Castro cleared waivers and was outrighted to Triple-A Iowa on Friday, Andy Martinez of Marquee Sports Network reports.
The Cubs designated Castro for assignment Monday.
Castro was optioned to Triple-A Iowa on Friday, Meghan Montemurro of the Chicago Tribune reports.