The Pittsburgh Steelers, the first NFL team to sign all of its rookies, opened training camp with a bang Monday by reaching a four-year contract extension with safety Troy Polamalu. Polamalu became the league's highest-paid safety by agreeing to a deal that will pay him $33 million through the 2011 season, which will allow the 26-year-old to be in line for another long-term contract in his early 30s. Polamalu was scheduled to become a free agent after the 2007 season. He will receive $15.375 million in both guarantees and roster bonuses. With Polamalu slated to make around $2.85 million this season, the extension will net him slightly more than $30 million over the ensuing four years. From the Steelers' standpoint, they will keep one of the best safeties and one of the best playmakers in the league under contract for $6.6 million until 2011.