Sometime during the offseason, Wilbur Jackson will sit down with his wife and talk about his future with the Washington Redskins. And Jackson, who is finishing his second straight virtually inactive year, admits that one of the options he'll consider is retiring from football.

"I don't know what I'm going to do right now," said Jackson, who has had knee injuries the last two seasons. "I still enjoy playing, but this has been a rough two years. Retirement is one of the things I'll think about seriously, no question. But for now, I haven't gotten into anything very much.

"All I'm doing is trying to stay in shape and be ready if the Redskins need me. After the season is over, my wife and I will discuss everything thoroughly. Maybe I should stop playing, although I still enjoy the game. It's just a bad situation, with the injuries and all."

Jackson is playing out the option in his contract, but he says even if he had a long-term commitment, it wouldn't affect his thinking that much.

"With the injuries, a contract doesn't really matter in your thinking," he said.

"A lot of things run through your mind. I've hurt the same knee against the same team two years in a row. You wonder about that. For a ninth-year running back to be hurt so much, that's not good. You wonder about that, too."

Coach Joe Gibbs said that if Jackson talks to him about retiring, he'd advise him to keep playing.

"Wilbur still is a talented, talented back," Gibbs said. "He's still capable of gaining 1,000 yards, in my mind. It would be a mistake for him to retire. He's had a couple of bad breaks the last two years, but all he needs is a heck of a training camp to get into the groove. And he has to stay healthy."

That is hardly the situation either Jackson or the Redskins expected when they sent two No. 2 draft choices to San Francisco for him in 1980. That was the year Jackson, a No. 1 pick for the 49ers, took over for retired John Riggins and led the team with 708 rushing yards. It also turned out to be his last healthy season.

In the midst of the Redskins' success this year, Jackson has become a forgotten man. He practices every day, usually masquerading as an opponent's running back against Washington's regular defense. He lifts weights, rides an exercise bike and follows a normal preparation routine each week. But on Sundays, he is a spectator, not a fan.

In training camp, he was a legitimate candidate for extensive playing time in the backfield. Some early exhibition fumbles set him back, but he had a good finale against Cincinnati and, with Joe Washington injured, he became Riggins' principal backup.

But in the season opener against Philadelphia, he hurt his knee on his fourth carry and hasn't played since. In 1981, he played six games, twice hurting his knee, before finishing the year on injured reserve. In two years, he has had a mere 52 carries for 189 yards.

The Redskins placed Jackson on injured reserve this year prior to the second game, against Tampa Bay. His knee was not badly injured, but with Washington already on injured reserve and with Nick Giaquinto having a badly sprained ankle, the team had only three running backs. Gibbs decided he had to make roster space for free agent Clarence Williams.

"I also remembered," Gibbs said, "that last year they thought Wilbur's knee would come around after a few weeks but instead it still wasn't better for a long, long time. I didn't want to take that chance this time."

Jackson said he "felt really bad about going on injured reserve in September. The knee wasn't as bad as last year, but I knew they were down in the backfield. I understand why they made the move. They had to have healthy backs."

Jackson understands and accepts his current situation. He is a soft-spoken, never-complaining person who works hard. He says the Redskins have treated him well, that he wants to play but that if he doesn't, he'll accept it as part of the game.

"I've told Coach Gibbs that I don't want to be activated unless there is a reason for it," Jackson said. "Everyone is playing well and why change that?"

His knee has been healthy since the season resumed following the players' strike. But to activate him, Gibbs must either cut a player or put someone on injured reserve.

"I'm reluctant to make any moves unless they are necessary," Gibbs said. "I've seen them backfire too many times. The three backs we have behind Riggins and Washington (Giaquinto, Clarence Harmon, Otis Wonsley) all have specific roles and all are playing well. There is just no room for Wilbur."

But Gibbs also realizes that Jackson can be a valuable player. Early this week, the Redskins considered activating him (he also can be activated in the playoffs), but backed off when a number of wide receivers were injured.

"We know he's there," Gibbs said. "We don't want to waste him. He could really help us in the playoffs."

Gibbs formally ruled out kick returner Mike Nelms from Sunday's game against St. Louis. Nelms, who has a muscle pull in his thigh, will be available for emergencies . . . The Redskins said fans attending the game should use ticket No. 1 to get in. That's the original home game against the Cardinals, on Sept. 26 . . . Receiver Alvin Garrett, who was supposed to be sidelined for two weeks with a bad ankle, practiced yesterday and will play Sunday. He eases a problem at receiver, where Virgil Seay has a bad hip and probably will be held out for a week . . . Mary Lou Riggins gave birth to a boy Thursday night at Fairfax Hospital. It is the Riggins' third child.