Escalona's elbow didn't respond as well as the Astros would like following his live batting practice session Wednesday.
"Escalona's arm, after he threw yesterday, just wasn't where he feels it needs to be, and really our doctors and staff feels it needs to be," Mills said. "We're going to get him some more tests on that to see where he's at, so he's probably not going to throw for a while with that."
Mills said left-hander Wandy Rodriguez, who's been dealing with back stiffness, is feeling better. Infielder Angel Sanchez, who injured his back falling down some stairs last month, continues to improve. He hit soft toss in the batting cage Thursday and fielded ground balls on each side of his body.
Mills also said third baseman Jimmy Paredes, a switch-hitter, was able to take batting practice from the left side of the plate only. He's been dealing with wrist inflammation since January.
"We're going to have to monitor him real close," Mills said. "He's still a ways away."