It was believed Wallace would replace Carlos Lee at first when he was traded, but after dealing Lee to the Marlins on Wednesday, the Astros moved Chris Johnson to first base and called up Matt Dominguez -- one of two players acquired from the Marlins -- to start at third.
"We've talked about [Wallace] and I don't think we've reached, to my knowledge, a decision on what we're going to do," Mills said. "Definitely, he's got to be in the mix, I would think, simply because what he did when he was here and what he was doing in Oklahoma City."
The Astros could be making a few roster moves at the All-Star break, with reliever Wilton Lopez and outfielder Justin Maxwell both on Minor League rehab assignments at Oklahoma City and due to return to the club following the break. Infielder Marwin Gonzalez could also return soon from his rehab assignment.