SEATTLE — Seattle’s “Big Walt” is finally saying goodbye.

Seahawks four-time All-Pro Walter Jones has retired after 13 years in which he became the standard to which all left tackles aspired — and most defensive linemen succumbed.

The 36-year-old Jones made the announcement in a team news release Thursday. It had been expected for months. Jones hasn’t played since Thanksgiving Day 2008 and has had two knee surgeries in that span.

The team is immediately retiring the number 71 jersey of the man Mike Holmgren has said is the best offensive player he ever coached — and Holmgren has coached Brett Favre, Joe Montana, Steve Young and Jerry Rice.

Jones’ is the third jersey the Seahawks have retired, following No. 80 for Hall of Fame wide receiver Steve Largent and No. 12, for their “12th Man” of passionate fans.

“What a great day to be a seahawk,” Jones posted on his Twitter page Thursday afternoon.

Washington Gov. Chris Gregoire is honoring Jones on Friday by declaring April 30 “Walter Jones Day” in her state.

Last week, Seattle drafted Russell Okung sixth overall and immediately proclaimed the rookie from Oklahoma State as Jones’ replacement for 2010. Okung will be the Seahawks’ second regular left tackle in 14 years.

Seattle used a sixth overall pick in 1997 to select Jones out of Florida State.

Within two seasons, the 6-foot-5, 325-pound Jones became the first Seattle offensive lineman to make a Pro Bowl. He ultimately earned eight more Pro Bowl selections, his last for the 2008 season.

Jones quickly became the anchor upon which Holmgren steadied a previously meandering franchise. Jones led an offensive line that helped Shaun Alexander to what was then the fourth-best rushing game in NFL history, 266 yards against Oakland on Nov. 11, 2001.

On Sept. 29, 2002, Alexander ran behind Jones en route to an NFL-record five first-half touchdowns against Minnesota.

In 2005, Jones plowed rushing lanes for Alexander’s MVP year, during which he amassed a Seattle-record 1,880 rushing yards and what was then an NFL-record 28 total touchdowns. That season ended with Seattle’s only Super Bowl appearance — and with Jones’ offseason training regimen of pushing trucks in the stifling summer heat of the South gaining national attention.

Through it all, and through contracts that made him rich and then richer, Jones wowed teammates with how humble and grounded he remained.

The best testament to Jones’ value to the Seahawks may be found in the last two years. While he missed the final weeks of the 2008 season and all of 2009 following microfracture knee surgery and a follow-up procedure, three-time Pro Bowl quarterback Matt Hasselbeck had the worst statistical and most injury-filled seasons of his career.

Seattle tried four left tackles in Jones’ place last season. They all failed.

Hasselbeck posted a team video tribute to Jones on his Twitter page minutes after Thursday’s announcement, with the title “thankyouwalter.”