Brackett, the Colts' defensive captain, is out with a bruised shoulder, while Sims sprained a knee during the Texans' 34-7 victory in Indianapolis' season opener.
Brackett is said to be hoping that he will be able to go, but coach Jim Caldwell sounds as if he is putting the nix to that idea:
"Well, I can tell you when I said those two guys are out, unless some miracle occurs, OK?" Caldwell told reporters Wednesday. "And it’s happened with a couple guys.
"That’s why often times we kind of avoid even telling you that because of the fact that if they happen to pop up, if he happens to come through and say, 'Coach, you know what, I can go,' then we’re going to let him go. And I’ll just have to come back and tell you I was wrong."
Second-year linebacker Pat Angerer would likely shift to middle linebacker should Brackett, indeed, not be able to go. The Colts have also re-signed linebacker Nate Triplett, who was one of the final cuts for Indianapolis.