Losing Wallace without a comparable replacement being brought in as a corresponding move would compromise the team's current receiver depth, but that depth is already incredible.
Emmanuel Sanders, who seemed poised to be Wallace's starting counterpart last year before an injury allowed Antonio Brown to emerge, is more than capable of being a force opposite Brown.
Now, for this to work, the team will need to make sure they bring Jerricho Cotchery back. They are likely working on just that type of deal, but nothing has been completed. Cotchery brings a possession receiver element to the team and would figure in perfectly as a third receiver in the slot.
The Steelers could bring in a late-round receiver like B.J. Cunningham of Michigan State if they wanted to have further depth at the fourth spot. They could also elect to give Tyler Grisham his long-awaited opportunity.