Diaz (hamstring) fielded grounders and took batting practice Tuesday, Daniel Kramer of MLB.com reports.
Diaz was placed on the injured list May 26 with the left hamstring issue and Tuesday marked his first time fielding groundballs or taking BP since landing on the shelf. The 28-year-old has been running over the past week but won't begin a rehab assignment until after the Astros return for their upcoming homestand, which begins Friday.