It's unlikely Cordero will be activated before rosters expand on Sept. 1.
Cordero is still wearing a protective boot on his right foot, which is a treatment for the sesamoiditis he's experiencing. That's the same ailment that forced former Astros infielder Jeff Keppinger to undergo foot surgery a couple of years ago, but Cordero has avoided that.
"It's better by the day, and hopefully I can go on a rehab assignment soon," Cordero said. "It's going to be a little bit faster [to heal] than I thought, and that's helped me out. I don't know the days or when they plan to send me on a rehab, but hopefully I can come back sooner [than Sept. 1]."
Cordero, who flew to Miami on Wednesday to take another step toward gaining his U.S. citizenship, has appeared in only six games with the Astros since coming over in a trade with the Blue Jays. He's allowed 13 hits and 11 runs in five innings, while blowing two saves and going 0-3.