Walter Football's newest NFL Mock Draft has Cam Newton, Marcell Dareus and Von Miller going with the first three picks, as has been common recently. They have the Steelers picking Texas cornerback Aaron Williams recently, and that pick, too, has been very common:
This is a tough spot for the Steelers. General manager Kevin Colbert takes the best players on his board, but the top prospects available are running backs, wide receivers and 4-3 personnel.
The best player who makes sense for the Steelers is Aaron Williams. Williams is a better fit for Pittsburgh's defense than Brandon Harris, and he can play free safety in addition to cornerback. So, if he fails at corner, he could always replace Ryan Clark down the road (think Antrel Rolle).
Looking further into later rounds, Alabama offensive lineman James Carpenter goes to the Steelers in the second round. They then take Miami lineman Colin McCarthy in the third, and Stanford nose tackle Sione Fua in the fourth. These picks all meet Steelers positional needs, and it shows they're paying attention - both Williams and Carpenter visited the Steelers recently.