The Cardinals will also take some extra position players -- among them, Pete Kozma, Ed Easley, Scott Moore and Stephen Piscotty -- who are not expected to crack the Opening Day roster to Memphis.
Those players, along with the relievers who do not earn a spot on the 25-man roster, will stay in Memphis after Friday's exhibition game and open the season in Triple-A.
Before making their final roster decisions, the Cardinals got at least one more look at Aardsma, who signed a Minor League deal with the organization on Wednesday. Aardsma gave up three runs in just one-third of an inning in Thursday's 6-4 loss to the Marlins. He also walked two.
"We're trying to see who fits best," manager Mike Matheny said, "and let them continue to show what they've got."
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.