Steelers WR Mike Wallace did not participate in the voluntary OTAs or the mandatory mini-camp. He might not show up to training camp on time, either.
Wallace is a restricted free agent (RFA), which means he can continue to negotiate a long-term deal as he holds out of training camp. The best case is that Wallace gets a deal done before the start of camp, but the two sides are reportedly far apart on compensation. The worst case is that Wallace goes the same route Vincent Jackson did in 2010, when he held out for much of the year only to return midseason so that he wouldn't lose a year of service and remain a RFA the following season.