[2][3] An unrated tight end prospect,[4] Petrus walked on as a fullback at the University of Arkansas but was moved to offensive guard for the 2007 season.

[5] He blocked for rushing tandem Darren McFadden and Felix Jones, both of whom eclipsed the 1,000-yard mark,[6] and was named to the All-SEC second-team.

[5] At the 2010 NFL Scouting Combine, Petrus completed 45 reps of 225 pounds (102 kg) on the bench press, which tied defensive linemen Leif Larsen and Mike Kudla for the second most since 2000.

[15][16] Petrus was waived on September 2, 2012, after the Giants were awarded offensive tackle D. J. Jones on waivers from the Philadelphia Eagles.

[18] The New England Patriots signed Petrus on November 13, 2012, to help with a depleted offensive line that included injuries to Logan Mankins and Dan Connolly.