The Pittsburgh Steelers knew entering the 2011 NFL Draft that they needed a defensive end to get into the pipeline in order to preserve the integrity of their 3-4 defensive front, which served as the foundation of their success during the 2000s.
They also knew that, in spite of the fact that they were set to pick 31st in the draft after reaching the Super Bowl the year before, that particular class was abnormally—extraordinarily—deep at the 3-4 defensive end position.
It is indeed something that was in discussion at the time, quite actively, to be sure.