The Seahawks have agreed on the parameters of a contract with free-agent linebacker Julian Peterson, who has spent the past six seasons with the 49ers.

Peterson's agent, Kevin Poston, said Tuesday the contract is for $54 million over seven years and includes $18.5 million guaranteed.

The Seahawks had no comment. A spokesman with the 49ers, who had been hoping to keep Peterson, said the team has been informed that a framework for a contract with Seattle is in place.

Delores Peterson, Julian's mother, confirmed from the family's Maryland home that her son was going to Seattle. She said Julian could not come to the phone because he was "swamped entertaining" dozens of friends who had piled into the house to celebrate his move from a last-place team that has gone 6-26 the last two seasons to the NFC champions.