The Washington Redskins returned to the practice field yesterday to begin preparations for the Dallas Cowboys, but quarterback Billy Kilmer, among many others, was unable to work.

While Kilmer, who has a sore back, is not expected to miss Sunday's game in Irving, Tex., against the first-place Cowboys, coach George Allen admitted yesterday, "He really does have to hurting not to practice."

Kilmer's never had back problems: not this bad," Allen added. "To write a lot of stuff now would be inaccurate because we can't tell (how bad Kilmer's condition is). But it's very disturbing."

Kilmer declined to comment on the injury. He did nothing during the 2 1/2 hour practice but stand around and watch Joe Theismann handle all the quarterback work.

Kilmer had a similar back problem the week before the season opener against the New York Giants, but he was able to play that Sunday, completing 50 per cent of his passes.

Kilmer's injury before the Giant game was diagnosed as "back spasms" and Allen said yesterday he was suffering from the same problem. But team sources reported that Kilmer was hit extremely hard several times in the Tampa Bay game, which may have contributed to his current condition.

Kilmer was not the only Redskin hurting yesterday. Allen announced that reserve linebacker Stu O'Dell, one of his most valuable special-teamers, will need surgery to repair torn cartilage in his right knee.

O'Dell has been placed on the injured-reserve list and the Redskin resigned linebacker Joe Harris to the 45 man team. Harris, who played in the Canadian Football League the past two seasons, was on the Redskin roster for the first two games but was cut two weeks ago when Allen decided to bring Brig Owens back to the squad.

There were many more missing from yesterday's practice, including linebacker Chris Hanburger, who is not expected to play Sunday because of a sprained ligament in his left knee. Hanburger said yesterday. "I'll know more in the next couple of days. I don't know if I can play or not.

"Right not, the biggest problem is the swelling. There's not a lot, but it prevents me from having full extension. I can stretch the leg all the way down, but I have trouble bending it back up. When I went back after I hurt it, I just couldn't run."

Pat Fischer's back also is still a problem.He came out in sweat clothes and ran alone on the artificial turf before going back to the training room for treatment. Defensive tackle Dave Butz, like Fischer a nonparticipant in the Tampa game, walked about four miles trying to improve his sprained ankle.

The starting backfield of Mike Thomas and John Riggins also did a lot of watching. Thomas' left hamstring is still sore and Riggins took some sever jolts in the ribs Sunday. Both said they would play against Dallas.

Wide receiver Frank Grant was given a day off to recuperate from the broken nose and broken tooth he received against the Bucs. Receiver coach Pete McCulley said he expects Grant to return to work later this week.

Tight end Jean Fugett, who had a bad cold last week and played sick against Tampa, also was allowed to skip practice.

Right guard Terry Hermeling (slightly separated right shoulder) and receiver Larry Jones (bruised buttock) dressed for the workout but did not participate.

Allen insisted it was too early to make decisions on the status of his injured players for the Cowboys. It appears Hanburger will not play and Fischer's chances are not good. Everyone else should be available.

"I'm concerned about all of them," Allen said, "It's the biggest game of the year and if you have all these guys out you ought to be concerned. You've only got so many days to get ready for a big game, and we're practicing with makeshift units."

With O'Dell out for the year, special teams coach Paul Lanham said he would give rookie running back Clarence Harmon and linebacker Harris a shot a working with the first units for punts and kickoffs . . . Harris said he had a least two offers - from the Eagles and Colts - last week to join those teams. "I just wanted to sit back "When coach Allen cut me, he said there was possibility of coming back. I got a real break" . . . The Redskins are now ranked eighth in the NFC in total offense (seventh rushing and passing) and seventh in total defense (fifth against the rush. 10th against the pass). The Cowboys have the No. 1 offense (first rushing, second passing) and No. 3 defense (fourth against the rush, third against the pass).