It will be the third stint for the 35-year-old Atchison with the Red Sox this season. He has a 4.73 ERA in seven relief appearances, and has appeared in 103 games over five seasons with Seattle, San Francisco and Boston.
Atchison will be available for Friday night's interleague game against Pittsburgh.
Bowden has been solid out of the bullpen for Boston this spring, with a 1.29 ERA in six appearances. He has a career record of 2-2 with a 5.82 ERA.