Helsley was recalled from Triple-A Memphis on Saturday.
Helsley has a poor 5.06 ERA in 32 innings for Memphis, but he's actually fared better in 10.1 frames at the big-league level, posting a 3.48 ERA. His 29.3 percent strikeout rate in the majors is strong, but he's walked too many batters (12.2 percent). Edmundo Sosa was optioned in a corresponding move.