Steelers coach Mike Tomlin said Tuesday it's likely a few players would miss time early in the practice week, and that's what happened.
With it being early in the week, it isn't particularly troublesome, but these names appearing on the same report tomorrow would be more of a concern.
The wide receivers, Wallace and Sanders, would present the biggest problem. There are only four receivers on the roster (Antonio Brown and Jerricho Cotchery practiced, fortunately), and further absence from either one of them could alter the offense the Steelers have run most frequently this season (3WR, 1RB, 1TE).
At first blush, one option to replace either of the receivers would be using Miller split out wide in certain formations - something he does now - but he's injured as well.
BTSC will have more injury news as soon as it becomes available.