Redskin cornerback Lemar Parrish insisted yesterday he is a fast healer, but Redskin team physician Stanford Lavine said he did not think the All-Pro cornerback would be available to the Redskins at least until the playoffs, if then.

Parrish suffered what Lavine described as a fractured radius in his right forearm and said he would be in a cast for at least eight weeks. He added there was no way Parrish could play his position with that sort of injury until it heals properly.

Parrish was hurt on the fifth play of the second period as he came up to defend against a sweep around the right end by Giant tailback Bobby Hammond.

"I was just trying to make the tackle and I was in a position where I couldn't put my shoulder into him," Parrish said later, his arm hanging from a sling and encased in a heavy cast from his wrist to his elbow. "So I just stuck my arm in there to try to make the tackle.

"As a result, I must have caught a shoe or a knee right on the bone. You talk about hurt . . . I knew it was broken the minute it happened. But I've always been a quick healer. I want to come back in four weeks at least I'll be trying.

"I really want to play. I can't stand watching. But what the heck, that's football."

With Parrish out, the Redskins turned to third-year man Gerard Williams at the cornerback, with second-year safety Donnie Harris coming in as the fifth back in the nickel defense.

"I'm ready to play," said Williams. "You hate to see anything like that happen, but that's why I'm here. I played the position all last year, it's not like I'm a rookie or anything. I've just got to do the job."

Several other Redskins also will join the injury list this week. Offensive tackle Terry Hermeling suffered a sprained knee late in the third quarter, and running back Ike Forte also had a sprained knee. Lavine listed both of them as questionable for the 49ers Sunday in Washington.

Fullback John Riggins, who gained 78 "of the toughest yards of my life," was sore all over with a hip pointer, several contusions on his arm and a jammed neck. "It'll ache . . . tomorrow," he said, "but I'll be all right for next week."

Tailback Mike Thomas dressed, but once again did not take part in the pre-game warmup and did not play because of his sore right foot. Lavine said afterward that Thomas is cleared to practice "any time he feels he can. It's up to Mike."