PITTSBURGH -- The Pittsburgh Steelers continued their offseason roster purge Friday, announcing veteran linebacker James Farrior and defensive end Aaron Smith will be released before the next league year begins March 13.

"Both Aaron and James have given their all during their time in Pittsburgh, and we appreciate their efforts and leadership they gave us," team president Art Rooney II said in a statement.

Farrior and Smith served as the backbone of a defense that led the franchise to two Super Bowl titles and three AFC championships over the last decade, a period in which the Steelers defense finished ranked in the top 10 in the league every season.

The duo join wide receiver Hines Ward and guard Chris Kemoeatu, who were told earlier this week they also will be cut as the team addresses salary cap concerns and an aging roster, particularly on defense. Nose tackle Chris Hoke retired in January due to lingering neck problems.

The 37-year-old Farrior, a two-time Pro Bowl selection, had 78 tackles in 14 games last season. Though he stayed relatively mostly injury free in 2011, Farrior was due about $2.8 million in 2012, and the Steelers are making a series of moves to get under the projected salary cap of around $120 million.

"James Farrior has been a rock for the Steelers but the Turk takes no prisoners-he's gone," Farrior's agent, Ralph Cindrich, said Friday on his Twitter page.

Quarterback Ben Roethlisberger and linebackers LaMarr Woodley and Lawrence Timmons already have agreed to restructure their contracts in the hopes the team can free up enough cap space to keep restricted free agent wide receiver Mike Wallace.

Farrior was so highly respected by his teammates they named him a defensive captain in each of his final eight seasons. He had 30 sacks and eight interceptions during his 10 seasons with the Steelers after coming over from the New York Jets. He likely will be replaced by Larry Foote, who has been a capable spot starter throughout his career.

It's uncertain whether Farrior will attempt to sign with another team, something Ward vowed to do after the team told him he would be let go on Wednesday.

Smith, however, is expected to retire. One of the top defensive ends in the league during his prime, the 35-year-old Smith has struggled with staying healthy in recent years. He ended the 2007, 2009 and 2011 seasons on the injured reserve list.

He was limited to four games in 2011 due to a neck injury. He underwent surgery and was considering a comeback but told reporters in January he wasn't sure whether he would play again.

"To (change teams) now would just taint the whole idea of being a Steeler," Smith said. "You're not really playing for the money at this point. How much is enough?"

Smith had 44 sacks during his 13-year career, 10th on the club's all-time list, and made the Pro Bowl in 2004.

Information from The Associated Press was included in this report.