Wallace hit sixth in the lineup and finished 0-for-4 in Houston's 6-0 win over Milwaukee. He reached on an error in the fifth.
"Obviously not getting a hit isn't the ideal situation," Wallace said. "But I think what it does is it lets you calm down and tomorrow you can go out there with a calmer approach."
Wallace, who came to the Astros from the Blue Jays organization, hit .301 with 18 homers and 61 RBIs for Triple-A Las Vegas. He was in the lineup Saturday at first base, the position previously occupied by Lance Berkman, who was traded to the Yankees. Wallace said he's not going to try to be Berkman.
"Lance is such a good player," Wallace said. "I don't think you can ever take someone's shoes. My goal is to go out there and play hard and be prepared. You can never try to live up to someone's milestones."
Wallace has some connections with a few current Astros. He played against starter Bud Norris in high school in Marin, Calif., and played on the same select team as catcher Jason Castro growing up.
"I was excited," Castro said. "It was a neat situation. I played with and against him for a while now, so I know what a great addition he will be."
Norris said he called Wallace right after he heard he was traded.
"We've kept in touch over the years," Norris said. "I'm happy to be pitching with him and not against him."
The Astros traded outfielder Anthony Gose, who they acquired from the Phillies for Roy Oswalt, for Wallace. Upon being traded, he traveled to Okalahoma City for Triple-A Round Rock's game Friday. But he didn't play because he was getting the call up to the Astros.
Wallace's family flew into Houston to watch him play.