Most improved units: AFC

Mike Adams and David DeCastro should help to fortify the Pittsburgh Steelers' offensive line. US Presswire

With the NFL draft and the better portion of free agency behind us, most teams have made their biggest moves to improve their rosters for the 2012 season. Looking at the additions so far, I see several units that have been improved this offseason. On Thursday, I examined those units in the NFC. Today, let's take a look at the AFC, focusing on the upgrades by the Pittsburgh Steelers, Buffalo Bills and Indianapolis Colts.

Pittsburgh Steelers
Offensive line