Defensive tackle Bob Slater, the man who has been a Washington Redskin for two years and never played a down in a regular-season game, lives a peculiar existence in this week's minicamp.

He is a rookie hiding inside a veteran's uniform, an optimistic player fighting a pessimist's past, a concerned man living behind a hulking, country-boy facade.

Slater is practicing with the Redskins for the first time since November 1984, when his left knee started getting in the way of a promising career.

By itself, this is a triumph.

Yet it presents even more problems. Every move he makes, he hopes his knee makes it with him.

"I don't know if the leg will hold up or not," Slater said after practice at Redskin Park. "It may be waiting for one special move and then, pop, blow out again. Hopefully, if there is such a move, I will never make it."

Two years ago, Slater was the Redskins' top draft choice out of Oklahoma, full of hope and pass-rushing power, with a virgin left knee.

Now, with his leg ugly from three operations and shaved to allow a brace to be taped on, he admits that if he doesn't play this season, he probably never will play in the National Football League.

"Realistically, this will probably be it," Slater said. "I'm coming out and trying to make it. If the leg doesn't hold up, I'll try to figure things out then. How do you approach that? There you are, crippled and without work. How do you deal with that?"

If it's any consolation, Slater, 25, has had more time to practice being crippled and without work than he has had time to practice football.

Two years ago, he missed half of his first minicamp while his agent worked on his contract. He was healthy until the last 1984 preseason game, when he sprained a ligament in his left knee as he tried to jump over a pile of bodies to get to a New Orleans running back named George Rogers.

One of the players he was trying to leap over dove out of the pile, hitting Slater in the back of the knee. They carried him from the field.

He went on the injured reserve list and began practicing again late in the year. But in November, his knee buckled during a drill and he again was carried from the field. He underwent arthroscopic surgery and was gone for the season.

He had more minor surgery in the offseason but thought he was fine until one spring day a year ago. He was running between cones on the field, getting ready for minicamp, when his knee popped out again.

"Last drill, last cone, last day before minicamp," Slater said. "What luck."

This time, he had reconstructive knee surgery to rebuild his interior cruciate ligament. He spent the 1985 minicamp in a bed at Sibley Memorial Hospital.

"Nobody can be more disappointed in the way things have gone than I am," Slater said. "For the management and the coaches, life goes on. They bring in a new player and keep on going. But for me, it stops. I have to start over from the beginning. I can't just get a new leg and go on."

Rehabilitation has been slow. There's been time to fish, time to work on the house, time to become a father and watch the son grow to nearly 7 months old.

Slater has measured success by walking laps in a swimming pool in August, then running them in January. "They do look at you kind of funny when you hop into a pool with running shoes on," he said.

No knee ever is perfect again after surgery, but Slater says he expects his bad knee to be as strong as his good one by this fall.

Everything points to this fall. Right now, the Redskins picture Slater the way they did in 1984. He is a top prospect, nothing more, nothing less.

"It's good for him to have some bodies flying by him, to gain some confidence," said Coach Joe Gibbs. "He is getting the work he needs right now."

If Slater stays healthy, the Redskins' defensive line becomes SRO. At the end of last season, the team carried three tackles: starters Dave Butz and Dean Hamel and reserve Tom Beasley. They figure to return, and there also are Slater, Darryl Grant (knee surgery) and top draft choice Markus Koch, an end who might move to tackle.

"We have five or six guys fighting for three or four spots," Slater said. "That's more than we have room for. Basically, we're talking about a fight to the finish, and I sure hope to be there."

The first day of the Redskins' latest kicking competition ended yesterday with veteran Steve Cox on top of the pack. Cox, the team's punter last season, made 17 of 20 field goals between 30 and 45 yards out; incumbent Mark Moseley, 16 of 20.

Free agent Jim Asmus, formerly with the Denver Gold of the U.S. Football League, also made 16. Four other free agents competed: Steve Willis was successful on 15 kicks; former Maryland kicker Jess Atkinson, 14; Rocky Costello, 13; and Paul Woodside, 11.

The Redskins would like to take no more than four kickers to training camp in July, special teams coach Wayne Sevier said.