Boston's Atchison optioned to Triple-A Pawtucket
Right-hander Michael Bowden was recalled to take Atchison's place.
Atchison came in after starter Tim Wakefield struggled. He held the Athletics to one run over three innings in a 15-5 loss. Atchison, who was up with Boston for the fifth time, was recalled Friday. A doubleheader is scheduled for Saturday.
Bowden has appeared in six games this season, allowing one run in seven innings.