The Reds outrighted Buchanan to Triple-A Louisville on Tuesday.
After being acquired from the Phillies a week ago, Buchanan was added to the Reds' 40-man roster Saturday. He made his Reds debut later that day, tossing 3.1 innings out of the bullpen against the Brewers and giving up one run on two hits and two walks. He was designated for assignment a day later and will now stick around in the organization after clearing waivers.