In addition, he was a three-year starter on the school's basketball team and competed in track and field, achieving a career-best shot put of 45–11.

[4][5] He entered training camp competing to be a back-up guard against the Steelers' 2009 third-round draft pick, Kraig Urbik.

He ultimately lost the starting job to Trai Essex and was named at backup guard and right tackle to begin the season.

On November 29, 2009, he received his first career start in a Week 12 loss, to the division-rival Baltimore Ravens, after replacing an injured Chris Kemoeatu at left guard.

Foster returned to the starting position on December 20, 2009, against the Green Bay Packers and remained there for the last three games of the regular season, as the Steelers ended with a 9–7 record and missed the playoffs.

On November 14, 2010, he made his first start of the season, replacing an ineffective Essex at right guard, in a 39–26 loss to the New England Patriots.

The Steelers finished atop the AFC North with a 12–4 record and Foster went on to start at right guard in a 31–25 loss to the Green Bay Packers in Super Bowl XLV.

[8] Foster entered training camp in 2011 competing with Kemoeatu, Doug Legursky, and Essex for both starting guard positions.

He lost the starting right guard position to Legursky but was named the starter for a Week 2 victory over the Seattle Seahawks.

After defeating the Bengals in the AFC Wildcard, they went on to lose the divisional round to the eventual Super Bowl 50 champion Broncos.