of the 2012 NFL Draft. He was the first offensive guard taken in the first round by the Steelers since Kendall Simmons in 2002 and was one of four Stanford players taken in the first two rounds of the 2012 NFL Draft. On June 23, 2012, the Pittsburgh Steelers signed DeCastro to a four-year, $7.81 million rookie contract that also includes $6.35 million guaranteed and a signing bonus of $4.12 million. He entered training camp competing for a starting guard position with veterans Willie Colon, Ramon Foster, and Trai Essex. In the Pittsburgh Steelers' third preseason game against the Buffalo Bills, DeCastro suffered an injury and was forced to leave the game. After DeCastro was carted off the field, Steelers' head coach Mike Tomlin stated that the injury was a "potentially severe" right knee injury. The injury occurred when he was engaged with Bills' defensive tackle Marcell Dareus and had his teammate, offensive tackle Marcus Gilbert, accidentally fell on his right leg. It was discovered that he had suffered a torn collateral lateral ligament and a dislocated kneecap. On November 26, DeCastro was returned to the active roster, while Gilbert was placed on injured reserve. On December 9, 2012, he made his professional regular-season debut in a 24–34 loss at the San Diego Chargers. The next week, he earned his first career start during a Week 15 contest against the Dallas Cowboys. He finished his rookie year starting the last three games of the 2012 NFL season. 2013 With the departure of Willie Colon and Trai Essex, DeCastro entered the season as the Pittsburgh Steelers' de facto starter at right guard. He earned the start for the Steelers' season-opening 16–9 loss to the Tennessee Titans. During the tenth play of the game, DeCastro accidentally whiffed during a cut block and fell down onto the back of Maurkice Pouncey's right knee. Pouncey tore his ACL and was placed on injured-reserve for the remainder of the season. He was replaced by Guy Whimper during the Steelers' Week 9 matchup with the New England Patriots after suffering an ankle injury. He finished the season starting 15 games and was ranked the fifth best right guard by Pro Football Focus, as the Steelers finished 8–8 for the second year in a row. 2014 DeCastro returned in 2014 to complete his first full season after starting all 16 games of the regular season as the