Infielder Geoff Blum was reinstated from the disabled list along with left-hander Alberto Castillo.
Meanwhile, catcher Robby Hammock along with pitchers Sam Demel and Ryan Cook were promoted from Triple-A Reno.
"He's a switch-hitter, can play anywhere in the infield," D-backs manager Kirk Gibson said of Blum. "Robby Hammock, third catcher, he had the most experience and he's also very versatile. He can play anywhere, really, on the whole diamond."
With rosters expanding in September, Gibson did not want to run short on pitching in case the team finds itself in an extra-inning game.
"There's a lot more matching up that's going to go on in this last month, so we have three lefties now as well as the additional right-handers," Gibson said.