Castro has been out since July 8 with right knee effusion, which is discomfort in his surgically repaired knee. He hit .301 with two homers and 12 RBIs in his last 83 at-bats before going on the DL, and hit .462 (6-for-13) during his Minor League rehab at Oklahoma City.
"He's swung the bat so well on his rehab, we're getting him back at a good time -- it appears, anyway," Astros manager Brad Mills said. "There's no doubt a guy with his tools and his ability, to get him back is going to be nice."
Castro missed all of last year after undergoing ACL surgery and had been catching about two out of every three games prior to his knee acting up, splitting time with Chris Snyder. Corporan hit .304 with a .353 on-base percentage in his last 16 games.
"There's no doubt he really helps us out offensively," Mills said. "He's swung the bat really well during the whole rehab experience."