The Red Sox optioned Kelley to Triple-A Pawtucket on Thursday, Michael Silverman of the Boston Herald reports.
Kelley's first stint in the big leagues lasted just two days, with the right-hander getting tagged for three runs in one inning in his lone relief appearance Tuesday in Toronto. He'll cede his spot in the Boston bullpen and on the 25-man roster to Heath Hembree (forearm), who was activated from the 10-day injured list in a corresponding move.