The Red Sox have optioned right-hander Alfredo Aceves to Triple-A Pawtucket.
Boston made the move following Wednesday's 6-5 victory over Oakland and one day after Aceves had a dismal outing in a 13-0 loss to the Athletics.
Aceves allowed eight runs, seven earned, and seven hits in 3 1-3 innings. He walked four and committed a pair of balks before he was pulled.
Aceves also made a throwing error after failing to cover first in time as the A's capitalized on Boston's blunders while the conditions deteriorated in a steady, blowing rain.
He is 1-1 with an 8.66 ERA in five games. There was no word on a corresponding roster move.