Mike Gibson, Ben Hamilton, Chester Pitts and Tyler Polumbus started at left guard for the Seattle Seahawks last season.

No wonder the team went after Robert Gallery when the free-agent negotiating period opened Tuesday.

GalleryGallery and Seattle agreed to terms on a three-year deal, according to ESPN's Adam Schefter. The contract length suggests this will be a relatively modest deal financially for Seattle, a bit of a surprise.

Gallery, 31, missed four games last season and 10 in 2009, but he's a significant upgrade at the position for Seattle. The team has struggled to find a long-term starter at left guard since losing Steve Hutchinson to Minnesota following the 2005 season.

The line has been a mess overall. Seattle started 11 combinations last season alone, but the line is taking shape. First-round draft choice James Carpenter projects as the starter at right tackle, with third-rounder John Moffitt at right guard. Max Unger will step in at center, with Gallery at left guard and 2010 first-round choice Russell Okung at left tackle.

For the first time in years, Seattle has what appears to be a coherent, sustainable and promising plan for its offensive line. Gallery's durability is the biggest concern. The Seahawks felt good about adding another veteran guard, Mike Wahle, several years ago. His injury problems prevented him from holding down the job for long, however.

Gallery's connections to new Seahawks assistant head coach/offensive line Tom Cable were important in getting this deal done. Both were together in Oakland for years. Gallery let it be known he wanted to leave Oakland and stay with Cable. Cable's presence means the Seahawks know what they're getting from an injury and production standpoint.