Steelers WR Mike Wallace didn’t report for training camp or the club’s first three preseason games, but the Pittsburgh Post-Gazette reported that Wallace was expected to return after the Aug. 25 game at Buffalo. WR Antonio Brown is capable of being a go-to guy, and the Steelers have enough capable wideouts to have a potent passing game if Wallace isn’t in the picture. However, Wallace’s presence is key to the offense. At the least, his return bumps Emmanuel Sanders and Jerricho Cotchery into more complementary roles — parts they can play very well. Also, Wallace’s rare speed puts great pressure on a secondary. Moreover, Wallace and Brown complement each other well and make each other better, according to one coach who knows the Steelers’ personnel. “One balances the other,” the coach said, calling the duo a “two-headed monster.” When defenses began to key on Wallace a season ago, Brown “rode (the) wave,” the coach said.