Wilbur Jackson, veteran running back of nine years and two weary knees, announced his retirement from the Washington Redskins today from his home in Ozark, Ala.

"Playing nine years is a long time, especially when you are a running back. There's always a time when you have to think about retiring. It's a decision I have made and it's a decision I have to live with," said Jackson, 31, who came to the Redskins from the San Francisco 49ers before the 1980 season in exchange for two draft picks.

Jackson chose to end his National Football League career on a day when 56 rookies and free agents, and six veterans reported here to begin the Redskins training camp, breathing new life to a new season.

Jackson delivered this requiem: "You have to think about your pride. I wanted to leave before I was told to leave."

Jackson spoke in quiet terms of reconciliation, rather than in the loud, confident terms of a running back who has run for 700 yards or more in four seasons (including 1980 with the Redskins), because, really, he was a man out of options.

Jackson was unsigned for this upcoming season. Last season, the former University of Alabama standout earned a base salary of $170,200, seventh highest on the Redskins. Yet, in a physical sense, last year was hardly profitable for Jackson.

In the season opener against Philadelphia on Sept. 12, he suffered the third knee injury of his career (and second in two seasons) and spent 3 1/2 months on the injured reserve list. His season was reduced to 12 carries for 33 yards, including 27 in the playoffs.

Thus, it was a combination of his high salary, age and beaten knees that kept Jackson from reaching a contract agreement with the Redskins.

Today, Jackson said his knees felt fine.

"But they felt fine last year, too, and look what happened," he said.

Ronald Simon, Jackson's Minneapolis-based attorney, said today, "Wilbur was concerned that with his high salary, it would behoove the club to cut him in training camp. Our feeling was that the club would not want to pay him that much money, if he was not going to play much."

Simon said during negotiations with Bobby Beathard, Redskins general manager, he tried to gain a large "reporting bonus" as security, fearing that Jackson would work hard to get into condition, play with the team during the exhibition season, then get cut. The Redskins, who do not guarantee contracts, said they could not justify such a large bonus.

"It's really too bad because Wilbur has had such tough luck over the last two years. He is such a talented player and a good person. His interests were always with the team," said Coach Joe Gibbs. "But I think this is a decision that each player must make for himself."

"I have no reason to be bitter," Jackson said, adding that he really does not want to play for another NFL team or in the U.S. Football League.

"I think Wilbur understands the club's position," said Simon. "Probably, no other team will contact him now because of his high salary. We're not going to make any extensive efforts towards contacting any teams, either."

"I'll sit back and wait for a while before making any decisions," Jackson said, adding that he will fly to Washington this weekend to pick up his Super Bowl ring.

"I'll probably fly back to Alabama the same day. The ring is something I will always cherish. It's something I will keep with me for the rest of my life," he said. Quietly, he then hung up the phone and his career.

The six Redskins veterans who reported early were quarterback Bob Holly, wide receiver Cris Crissy, tight end Mike Williams, defensive back Greg Williams, linebacker Stuart Anderson and punter Jeff Hayes . . . Twenty or so players, who did not get physicals during minicamp in May, passed their physicals today . . . Tickets are still available for the Redskins' two home preseason games at RFK Stadium, against Cincinnati on Aug. 12 and Miami on Aug. 19 . . . The Redskins roster is at 110 with the addition of six players from the Canadian Football League: cornerback Leo Gray, defensive tackles Bruce Radford and Leon Evans, linebacker Stan Holloway, guard Norm Hopely and defensive end Ken Brown.