Aardsma walked the first batter on four pitches and allowed a single before escaping the inning without a run scoring.
"We bring guys in here with the purpose of seeing how they can make our team better," manager Mike Matheny said. "And the only way we can see that is when they get on the mound and show what they have in comparison to others. That's how David is going to fit in with this, and I'm anxious to watch him compete."
Aardsma was a free agent following his release by Cleveland on Friday after the Indians had determined he would not crack their Opening Day lineup. He continued to throw at a facility in Tempe, Ariz., before deciding to sign with the Cardinals.
Aardsma's deal does not include a guaranteed Major League roster spot, but rather a fresh opportunity. He said he is willing to begin the season in Triple-A if the Cardinals choose not to bring him to Cincinnati next week.
"One of the things I told my agent is if I can get a chance to get into camp somewhere with somebody for at least a couple days, I felt confident that I pitched well enough to make the Indians team," Aardsma said on Wednesday. "But when everyone else is throwing amazing, it's hard. I know what I can do. I know how I was pitching and what I am capable of, and I just want a chance to show somebody else that."
With the Indians, Aardsma allowed three runs (two earned) on five hits in six spring innings. He struck out five and walked none. Had the Indians kept him in camp through Tuesday, Aardsma would have been due a $100,000 retention bonus. He requested his release once Cleveland had determined he would not break camp with the Major League team.
If the Cardinals decide to carry Aardsma on their Opening Day roster, he will need to be added to the 40-man roster. Pat Neshek is in the same spot, which means the Cardinals would have to clear one more roster spot if both are to be in the bullpen.
"I don't know what their decisions are," Aardsma said. "I don't know where the roster stands. I'm not really worried about it. I knew I threw really well with Cleveland, had a good spring, felt great, and I'm just going to try to continue that."
It had been assumed that Keith Butler, Jorge Rondon and Scott McGregor were fighting for the final spot in the bullpen. They now have to contend against Aardsma as well.
The 32-year-old has played parts of eight seasons in the Majors with seven different clubs. He was most recently with the Mets, for whom he posted a 4.31 ERA and 1.46 WHIP in 43 appearances last season. He has a career 4.23 ERA in 298 games and spent the 2009-10 seasons as the Mariners' closer.
Aardsma began his big league career in 2004 in San Francisco. A year later, he worked a bit with Matheny as his catcher during Spring Training. In 2006, he and John Mabry were teammates with the Cubs.
"He was a hard, hard thrower at that point," Matheny said of Aardsma. "It was getting up to 100 [mph], or close to it. He was more of a heaver, and what we've seen recently is he's pitching more but still has some good life on the ball. We're interested to see what we see ourselves."