ORCHARD PARK, N.Y. (AP) -The Buffalo Bills signed three offensive linemen, including guard Derrick Dockery, addressing of their biggest needs on the first day of free agency Friday.

The Bills also signed tackle Langston Walker, who became a free agent after voiding his contract with Oakland, and journeyman lineman Jason Whittle.

It was a significant triple-play for a team that struggled in pass protection and the running attack with a patchwork line. The moves came a day after Buffalo released veteran guard Chris Villarrial and prepared to lose veteran Mike Gandy to free agency.

Dockery, who spent the past four seasons with Washington, was considered the key addition. The Redskins' third-round pick in the 2003 draft, he had 61 starts in 64 career games with Washington.

Dockery is expected to take over at left guard, replacing Gandy. He'll play alongside tackle Jason Peters.

``Really a terrific day for us,'' coach Dick Jauron said. ``It was just an outstanding day. We've got a happy building. Our free agency is, maybe not totally complete, but with the addition of these three today, it's been a terrific time.''

Langston, listed at 6-foot-8 and 345 pounds, has spent his five-year NFL career with Oakland, where he played both the right and left side. The Raiders' second-round pick out of California, he has 33 starts in 66 career games and started all 16 games last season at right tackle.

Langston is expected to take over at right tackle. His experience is considered an upgrade over Terrance Pennington, who started nine games in his rookie season last year.

Whittle was the first to sign after agreeing to his one-year contract, worth about $800,000, early Friday morning.

A nine-year NFL veteran, Whittle is a versatile lineman who can also play tackle and center and has experience as a long snapper. He had two starts in 16 games last season with Minnesota and became an unrestricted free agent after his one-year contract with the Vikings expired Thursday.

Whittle played with Tampa Bay in 2003 and had two stints with the New York Giants (1998-2002 and 2004-05), where he played under Jim McNally, the Bills current offensive line coach. Listed at 6-foot-4 and 305 pounds, Whittle had 42 starts in 125 career games.

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