Atlanta signed Capel to a minor-league contract Dec. 7.
The Reds released Capel on Aug. 3.
Capel cleared waivers Sunday and accepted his outright assignment to Triple-A Louisville, Charlie Goldsmith of The Cincinnati Enquirer reports.
Capel was designated for assignment Friday.
The Reds optioned Capel to Triple-A Louisville on Tuesday.
Capel started in left field and went 1-for-2 in Thursday's 7-2 win over the Dodgers.
Capel's contract was selected from Triple-A Louisville on Tuesday.
The Reds reassigned Capel to minor-league camp Wednesday.
The Reds signed Capel to a minor-league contract Tuesday with an invitation to major-league spring training.
Oakland outrighted Capel to Triple-A Las Vegas on Wednesday, Melissa Lockard of The Athletic reports.