Mark Rypien, looking tired and uncomfortable, predicted yesterday he would return to the Washington Redskins sooner than expected after having arthroscopic knee surgery on Tuesday.

Doctors said Rypien would be sidelined six to eight weeks after damage to two ligaments was discovered. But Rypien said he could be back before then.

"That's the long side of it, eight weeks," he said. "I'm going to try to get back sooner than that. That six-to-eight-weeks thing is just in case something doesn't go right with rehabilitation."

Rypien returned to Redskin Park briefly yesterday morning to have the bandage on his knee changed. He said he hadn't slept the previous night and was in extreme pain. He was given a pain-killing prescription, and after returning home, went to sleep and skipped an afternoon appointment with team physician Charles Jackson.

"He had a rough night," Redskins trainer Bubba Tyer said, "but he's doing fine. You probably couldn't convince him of it because this is a rough time of his recovery."

Rypien will rest the knee for a few more days, then begin taking ice and electrical stimulation to reduce the swelling. After that, he'll begin flexibility exercises followed by strengthening work. More News on Knees

Cornerback A.J. Johnson, who had reconstructive surgery on his right knee in June, has had an amazing recovery and may be cleared to play this season. He was thought to be out for the entire season, but his rehabilitation has gone so smoothly that it's possible he could be back at practice in late November.

Tyer said his goal was to get Johnson back on the practice field in December "and that there's a chance he would be available to play late in the game, probably in some situational-type things."

"They told me it would take about six months to get all the strength back," Johnson said. "I'm anxious to get back, but I don't want to do anything that would be taking a chance. . . . I'm a lot better, but there's still a long way to go."

Meanwhile, tackle Mark May has had a much slower recovery. After an arthroscopic cleanup procedure last month, May was expected back in October. But it now appears that just returning to the practice field in October may be goal enough. . . .

Defensive end Fred Stokes's tricky left shoulder has held together so nicely the last couple of weeks that the Redskins are reluctant to change the way he's being used. He's now tied with Wilber Marshall for the team lead in sacks (two) and line coach Torgy Torgeson said he would continue to use Stokes as a pass-rushing specialist.

Said Stokes: "It's working out just fine. But when I get completely well, I want to be in there. It wouldn't be fair to the team to put me out there if I'm less than 100 percent. I'm gaining more confidence in it all the time, but I really haven't played that much this season. There's still things I could improve on." . . .

Defensive lineman Eric Williams, the only player to miss Wednesday's practice, returned to work yesterday, saying his sore left shoulder "was a lot better."