Cornerback Pat Fischer was released from Sibley Hospital in Washington this afternoon, but it probably will be the end of the week at the earliest before the 17-year NFL veteran arrives at the Redskin training camp here to test the pinched nerve in his back.

Fischer, first hospitalized and put in traction here 11 days ago, said he felt "quite a bit better." would take physical therapy at team physician Stanford Lavine's office for two or three days and then attempt to run. He could not predict when he would be able to resume drills here.

"You're asking me a question I wish I knew the answer to," said Fischer shortly before his hospital discharge. "I'd be very comfortable if I knew those answers."

Publicly, coach George Allen insists that Fischer will be able to play again. Privtely, several team sources doubt that he will be able to ately, several team sources doubt that he will be able to second-year man Gerard Williams under a pressure-packed spotlight. He was burned for two touchdown passes in the team's 27-15 exhibition loss to the Dolphins in Miami Saturday night.

Allen already is bringing cornerback prospects into camp. With the third of six exhibition games coming up Thursday against Kansas City at RFK Stadium and a decision nearing on Fischer's status, it will soon be time for Allen to decide whether he will start Williams or attempt to trade for a proven NFL cornerback.

"Williams did some things that were good and some things that were not so good," Allen said today as he watched films of the Miami game. "He needs to play and play and play. He will play every play Thursday night. He needs all the work he can get.

"He's making good progress. It takes four or five years to make a good cornerback in this league. It's a tough position to play."

Williams looked badly beaten on a couple plays against Miami, and Fischer knew why:

"With his quickness he sould be a little more patient. Right now he wants to react to everything. This is the tough part. He is quick enough to wait and see. There's so much pressure focused on him now. It's like he's playing naked out there. If he can get through this and survive, he'll never go through a tougher season."

By necessity Williams is piling up playing time this exhibition season. But Allen is reversing previous form, playing the veterans much less than in his six previous preseasons, when veterans sometimes played on entire game.

Such action by Allen had drawn criticism that his teams were peaking too early in the seasons, as the reason why they have lost first-round games four times in five playoffs. The Redskins also lost nine players through injuries in the last preseason, including starters Charley Taylor and Paul Laaveg.

"We want to take a look at all these young guys," Allen said. "I don't want to overplay guys like (Billy) Kilmer, (Diron) Talbert.(Jake) Scott and (Ron) McDole. We're still playing to win (exhibition games), but not at the expense of playing the veterans all the way to win. The other thing is that three games in 11 days is to our advantage and will give everybody a lot of work."

Allen used 55 players of the current 60-man roster. Fischer> running back Mike Thomas (pulled hamstring) and punt returner Eddie Brown (groin strain) are injured; wide receivers Taylor and Frank Grant, both veteran starters, could have played, but were not used.

There were more negatives - another ineffective pass rush by the starting defense, a less-than-mediocre encore by No. 2 quarterback Joe. Theisman to his opening-game effort at Cleveland, Williams' inconsistency, live turnovers - than positives.

Defensive tackle Perry Brooks, who was cited by Allen as being one of the night's few bright lights for his pass-rushing, left the game with injuries to his left knee and ankle. Allen said Brooks, a 6-foot-3, 260-pound free agent, definitely would not be able to play against kansas City.

Dr. Lavine examine hime Monday in Washington and team sources here indicate that Brooks may be placed on injured reserve for the season.

Allen was upset with the manner in which Brooks was injured. It was on a "crackback block" delivered by a Miami lineman and therefore a legal block under current NFL rules. League rules were changed two years ago to outlaw such blocking tactics by receivers and running backs.

"It's a questionable type of block, a very vicious type of block," said Allen. "But by the rules, it's legal.

Allen said, "The pass rush at times was good and we didn't cover well. We never coodinated pass rush and coverage together" . . . Depending how Kilmer feels. Aleen said he likely will play his No.1 quarterback more than a quarter Thursday in the first of two home exhibition games . . . Allen was not satisfied with Theismann's play against Miami, but gave the backup quarterback an excuse for his three-interception, 10-for-26 night, all in the second half. "Joe had a disadvantage in that he was playing with a lot of different people in there," Allen said.

"We'll give Joe some different personnel when he's in there this week" . . . Safety Ken Houston needed four stitches to close a cut above his right eye, but he will be ready for Thursday' game, trainer Bubba Tyer said . . . More cornerback prospects are expected for tryouts Monday when practice resumes . . .Two-a-days officially ended a week ago, but there is a "special-teams" workout each morning, including drills for reserves . . . A small bat perched itself outside the team's press office in Adams Hall today, causing administrative types and assistant coaches to tread softly. Tim Temerario, director of player personnel, denied the intruder was a cornerback prospect.