Astin was released by the Reds on Monday.
Astin cleared waivers and was outrighted to Triple-A Louisville on Monday.
Astin was designated for assignment by the Reds on Tuesday.
The Reds optioned Astin to Triple-A Louisville on Thursday.
Astin had to come into Sunday's game in the second inning after Tim Adleman left with a neck injury. He gave up three runs over three innings, allowing three hits and two walks, striking out one.
Aston gave up three runs on four hits, two of them homers, Monday night against the Yankees.
Astin was recalled from Triple-A Louisville on Sunday.
Astin was optioned to Triple-A Louisville on Thursday.
Astin was recalled from Triple-A Louisville on Tuesday, Mark Sheldon of MLB.com reports.
Astin was optioned to Triple-A Louisville on Friday.