Today is the day Curtis Martin is giving the word.

It has been no secret that Martin, the NFL's fourth all-time leading rusher and the New York Jets' four-time MVP, would be retiring soon. It appeared unavoidable last November when he grimly said he would not attempt to play on his damaged right knee at all in 2006. It seemed etched in stone when newspaper, Internet, TV and radio outlets revealed earlier this week that his retirement announcement was near.

But today is the first time Martin will utter the R-word to the world.

Martin has embarked on a full day of activities by announcing his retirement on CBS' "The Early Show" in an interview with anchor Harry Smith that began at 8:30 a.m.

Then the "Curtmobile" — actually an SUV — really started to roll around New York City.

Martin stopped in at the Jets' 57th Street corporate offices to sit with the team's beat writers and football columnists, many of whom have covered him ever since he arrived as a restricted free agent from New England in 1998, for an hour-long interview.

After that, No. 28 and his entourage made nine more stops, at TV and radio stations around New York City, making his retirement official and thanking the fans for their support during his eight seasons as the heart and soul — "the bell cow," coach Herm Edwards once called him — of the Jets' offense through 2005.

"Retirement is not an end but a beginning," Martin told the Jets in advance of his appearance on CBS. "It is not giving up a position but more of a passing of the baton. And it’s definitely not a crossroad but a bridge that will further my pursuits within the NFL."

That last phrase is more than a polite tip of his hat to the league. Martin told the Jets something that may come as a surprise to many who thought they knew him and his interests.

"I have built my whole career towards ownership of an NFL team," he said, "and as I now prepare for retirement, I'm very close to fulfilling my dream."

Martin would not specify which team he's been in negotiations with since last year, although it is a team other than the Jets.

Martin is also going on this media blitz with one more message: that just as he's not forgetting the NFL, he's also not leaving New York behind.

"I've created a partnership with the City of New York," he said, "and we're working together to eradicate homelessness in the city."

The partnership with Mayor Mike Bloomberg's office plans to reduce homelessness in the city by two-thirds by 2009.

All of Martin's ambitious moves going forward stem from the remarkable set of events of the previous three years.

In 2004, the Pittsburgh native and Pitt product had the best season of his career. He led the NFL for the first time in rushing yardage with a career-high and Jets-record 1,697 yards; equaled Barry Sanders' record of 10 consecutive 1,000-yard seasons from the start of a career; climbed inexorably past the likes of Jim Brown, Tony Dorsett and Eric Dickerson on the league's career rushing list; helped lead the Green & White to the brink of the AFC Championship Game, and was named to his fifth Pro Bowl.

The next season was arguably Martin's worst, all because of that right knee — accidentally kicked by old Dolphins rival Zach Thomas in Game 2, then kicked again at Baltimore two weeks later. He finished with career lows in rushing yards, carries, yards per carry, receptions, yards per catch and scrimmage yards after calling it a season with four games to go to undergo arthroscopic surgery.

After surgery to remove damaged cartilage and other debris, Martin's knee was left with a degenerative bone-on-bone condition that finally was too painful even for him to overcome. He worked out all off-season to come back but was first placed on the Physically Unable to Perform list by head coach Eric Mangini at the start of last year's camp, then on the Reserve PUP list on Nov. 1, 2006.

"With the information I know about my future, it doesn't look like it's too bright as far as me having a further career," Martin said at the time, although from before that day until today, he declined to publicly state definitively that he would retire.

"I think his heart was saying one thing, and unfortunately the injury was saying something else," Mangini said that day. "He's got a pretty big heart, so I'm sure that battle was strong."

But Martin has never displayed bitterness or sorrow over what he said "may be the inevitable result" of his physical condition. He told CBS this morning:

"I'm leaving football knowing there's nothing I would've done differently," he said. "I gave my all on the field. I tried to be a standup guy, a man of integrity and a role model. ... I've appreciated all the fans who helped me reach this point in my career."

Now Martin is declaring this particular career arc over, and others are lining up to say how grateful they are to know him, to watch him play, to learn from him.

Among the many who are wishing Martin well in his future endeavors is NFL Commissioner Roger Goodell, who said in a statement:

“Curtis Martin represents everything an NFL player should be. He overcame many challenges to enjoy an outstanding career as one of the best running backs in the NFL. His on-field accomplishments were matched by an equally strong commitment to serving his community and being a positive role model off the field. We know that Curtis will continue to be successful and represent the NFL well as he moves into his next career.”

“The ability to play at such a consistently high level every week he took the field will be the enduring football legacy of Curtis Martin," said Jets general manager Mike Tannenbaum, who was instrumental in bringing Martin to the Jets in 1998. "He is a man of unparalleled integrity who treats everyone who crosses his path with a great deal of respect. I will always admire Curtis for the way he carries himself as a player and as a person.”

Mangini said that "in light of the league's recent concentration on personal conduct, Curtis serves as a shining example of how to handle yourself on the field and off. If you are looking for a hero, you don't have to look any further than Curtis Martin."

See "What They've Said About Curt" for more tributes about Martin.