Cornerback Joey Porter Jr. was listed as limited in practice, due to a back injury.
It doesn't take much to be listed as "limited" in practice; without more specifics, there's no way of knowing how much he did, or didn't, do.
The listing of Porter as having a back injury in advance of the Week 1 game against the Falcons is the next tangible move in the back-and-forth business wrangling between Porter and the Steelers over his second contract. He missed all of training camp on the physically unable to perform list, before passing a physical and being added to the roster when the limit moved from 90 to 53.
There are likely more moves to come. Obviously, a deal could be done at any time. If it isn't by Sunday, the Steelers plan to revert to their in-house policy of not negotiating contracts once the regular season begins.