Mills elected to become a free agent Tuesday, Charlie Goldsmith of The Cincinnati Enquirer reports.

Mills was outrighted Tuesday to Triple-A Louisville, Charlie Goldsmith of The Cincinnati Enquirer reports.

The Reds designated Mills for assignment Sunday.

Mills allowed five runs (two earned) on four hits and one walk over one inning in Saturday's 12-5 loss to the Padres.

The Reds selected Mills' contract from Triple-A Louisville on Tuesday.

Mills signed a minor-league contract Thursday with the Reds, Charlie Goldsmith of The Cincinnati Enquirer reports.

Mills (back) became a free agent Friday, Jordan Bastian of MLB.com reports.

Mills (back) was activated from the 60-day injured list, cleared waivers and outrighted to Triple-A Iowa on Thursday, Andy Martinez of Marquee Sports Network reports.

Mills underwent a procedure to remove a disc in his back Wednesday, Sahadev Sharma of The Athletic reports.