Porter agreed to the deal, which pays him $20 million guaranteed, according to a person with knowledge of the discussion who requested anonymity because Porter has not yet passed his physical and the contract may not be signed until tomorrow or Thursday.

Porter spent his first eight seasons with the Pittsburgh Steelers, who released him last week in a salary-cap move. He would have received $1 million if he was on the Steelers' roster today, and was set to make $4 million more for the 2007 season, the final one under his deal with Pittsburgh.

His 60 sacks rank fourth in Steelers' history, and he only figures to add more star power to a Dolphins defense that already has reigning defensive player of the year Jason Taylor and ranked fourth in the NFL in yards allowed last season.

And the linebacker position, which was already considered a strength with Pro Bowler Zach Thomas and Channing Crowder — who combined for 269 tackles in 2006 — now has a player in Porter that averaged more than 60 tackles annually in his tenure with Pittsburgh, a team he helped win the Super Bowl two seasons ago.

Porter's addition is part of what's becoming a major roster overhaul by the Dolphins, who were 6-10 last season, and new coach Cam Cameron.

Already, Miami has either released or traded seven players who started at least one game on offense in 2006 — offensive linemen Bennie Anderson, Damion McIntosh and Jeno James, quarterback Joey Harrington, tight end Randy McMichael, running back Sammy Morris and wide receiver Wes Welker.