I'm pretty sure it's primarily zone-blocking, with the emphasis being on lineman to stay on their feet.
For those who aren't aware, former Colts quarterbacks coach (1998-2000) Bruce Arians has recently been promoted as the offensive coordinator of the Pittsburgh Steelers, after serving as the Steelers' wide receivers coach for 3 seasons.
Word is that the Steelers offense will incorporate more no-huddle and 4 WR sets, which should be interesting in Steel Town especially. Roflisberger is very enthused by it, at least, he ran much more no-huddle in college than he has in the pros and has been clamoring for its incorporation for over a year.
Pugnacity, testosterone, truculence, and belligerence.