The Pittsburgh Steelers have signed coach Mike Tomlin to a two-year contract extension through the 2012 season, with an option year in 2013.

The extension was expected because the Steelers' policy has been to sign a coach before he begins the final season of a contract. Tomlin is only the franchise's third coach since 1969, following Chuck Noll (1969-91) and Bill Cowher (1992-2006).

Tomlin is 31-17 in three seasons, with two division titles, an AFC championship and a Super Bowl victory. During the 2008 season, he became the youngest coach, at 36, to win the Super Bowl when the Steelers beat Arizona 27-23.

''Mike Tomlin has proven to be one of the top head coaches in the National Football League in a relatively short time,'' Steelers president Art Rooney II said in a statement. ''His unique ability to lead the team and motivate individuals have been key factors in our success.''

The Steelers were 9-7 and missed the playoffs last season. They open training camp July 30 at Saint Vincent College in Latrobe, Pa.

The Pittsburgh Post-Gazette reported July 13 that Tomlin had signed a three-year extension through the 2014 season.

Tomlin made an average of $2.5 million US per season under the contract he signed upon succeeding Cowher in January 2007. His new contract is expected to at least double that.