Undrafted in '09 and a reserve until this season, he was Pro Football Focus's third-rated guard in the NFL, and the Niners' second-ranked lineman behind LT Joe Staley.
Two off-season knee surgeries slowed this 2011 fifth-rounder early on, and his sacks dropped from six last year to 1½ in '12. But he's returned to form in the playoffs, tipping two key Tom Brady passes in the AFC title game.
This rookie's 4.45 speed was contained to the sideline until Week 14. Since then he's played 107 snaps in six games as a return man (he had a 62-yard KR against the Pats) and change-of-pace back (a 15-yard TD run against the Falcons).