The departure of Gruttadauria comes four days after the Rams lost right tackle Fred Miller, also an unrestricted free agent, to the Tennessee Titans.

Both players are represented by agent Harold Lewis of St. Louis. The losses erase from the Rams two young but experienced starters on a blocking unit that quietly was developing into one of the best quintets in the league.

St. Louis could also lose key reserves Ryan Tucker and Andy McCollum. The versatile Tucker, who has been penciled in as the replacement for Miller, has signed an offer sheet with the Miami Dolphins. Because Tucker is a restricted free agent, the Rams have seven days to match the three-year, $8.5 million offer sheet. McCollum, a former starter in New Orleans, is being sought by at least three teams.

Gruttadauria, 27, will replace Aaron Graham as the Arizona starter. He will sign a four-year deal worth $8.6 million, with a $1.7 signing bonus. Gruttadauria met with Dolphins officials this week, but Miami re-signed incumbent Tim Ruddy instead. Graham is an unrestricted free agent and Arizona did not attempt to re-sign him, hoping to upgrade the position via free agency.

A four-year veteran, Gruttadauria signed with the Dallas Cowboys as an undrafted college free agent in 1995, was released in camp, then hooked on with the Rams the following season for training camp. He started 14 games in 1997, then lost his job in '98, when he played primarily on special teams. In '99, he started all 16 regular-season contests and three postseason games.

For his career, Gruttadauria has played in 49 games, with 35 starts. The former Central Florida star becomes the second NFL starting center in five days to switch teams, with Jeff Christy going from the Minnesota Vikings to the Tampa Bay Buccaneers on Tuesday.