Joe Theismann said yesterday he played the second half of the Thanksgiving Day game in Dallas and the final three games of the season with a separated collarbone in his left shoulder. He also insisted, "I don't think it affected my play."

Theismann said he was injured on the next-to-last play of the first half, when Cowboy tackle Randy White stood him up and defensive end Too Tall Jones "just about drove my shoulder into my mouth." He left the field, but played the second half and started Washington's final three games.

The injury was never reported to the NFL office. Said Theismann: "I didn't think it was my place to say anything about it.

"It wasn't important. I could still play. If anyone was going to say anything about my physical condition, it was going to be the training staff or management. I'm not looking for excuses not to play football. I practiced every day, and it did not affect my play.

"I had to take some aspirin-and that is all I took-and it's a good thing we had 10 days off after that (Dallas) game. It was painful for a while. What it feels like is a bad case of whiplash on the left side of my neck. I'll move my head a certain way and there will be some pain."

Theismann also has been nursing a sore chest since that game and has been playing on a wobbly left knee all year.

"I think I got a little cartilage tear in the Atlanta exhibition," he said. "I don't think it needs surgery. But to tell you the truth, my whole left side is pretty screwed up.

"but if I had felt in any way that my physical situation would have detracted from my performance, I wouldn't have played. I just felt I could play with it."

Theismann also admitted yesterday that not calling his own plays this season "really was a process that takes some time in getting used to.

"I'm not knocking it. But I'm a quarterback. For the last eight years I called my own plays and you have to totally turn that process off. You almost turn your mind off. It's like a man getting up a 8 in the morning for 10 years of his life being told he doesn't have to get up now until 8:30. I guarantee you, he'll just lay in bed not sleeping those extra 30 minutes.

"It was a matter of getting a feel for Joe (Walton, the offensive coordinator) and how he would call things. I'm not going to say I don't like it. I'ts the system the coaches want, and I won't argue when we were 6-0 and I won't when we were 2-8 at the end."

Theismann declined to comment on his benching in the final eight minutes of Saturday's loss to the Chicago Bears. For the first time in his professional career he would not answer questions in the locker room after a game.

"I just felt the best thing for me to do was to go home to my family," Theismann said, "What coul I say? I just don't have anything to say about it, and I still don't. I'd just prefer not to talk about that."

"Sure the booing bothered me. When I'd run the ball on first and second down, they booed, but I can't say they booed me because I was carrying out instructions. If they boo when I throw an interception, hell yes, I can accept that. I'm booing myself, too. I agreed with them."

Despite the dismal finish. Thiesmann insisted the 1978 season had been "a positive year for me. I finally got a chance to play. It was a great learning process and we all learned a lot.

"It's also pretty abvious that this is a team in transition. Just look at the roster and you'll see that. We're also a team that has to get stronger in certain areas. There's no way we could continue the way we were because time doesn't allow you to keep the same people in the same places over a five-six-10-year period."

Theismann was asked if he anticipated returning to the Redskins next season.

"Well, I haven't sold the house or anything," he said. "I anticipate working and playing football somewhere. This is the first year I haven't wanted to leave Washington . . . But I don't know what they want. I have no plans to be anywhere else, but I learned a long time ago that anything is possible."

Redskin Coach Jack Pardee said yesterday it is possible Theismann or anyone else who quarterbacks the team may get a chance to call his own plays next season.

"I've always contended I'd rather have the quarterbacks call their own plays, but we went this way because that's the way we thought we could win," Pardee said. "We will be discussing all of those things during the offseason.

"We're going to talk about using the 3-4 defense. I don't know if we'll use it more or less, but we'll have it ready to use. We're also going to learn how to run the football better next year, that's the reason our strength program in the offseason is so important."

Pardee said he basically agrees with General Manager Bobby Beathard's view that it will take several years to build the team through the draft. Pardee also said he prefers not to use 1980 draft choices to obtain veteran players.

"I hope we can do what Philadelphia has done-get lucky on some picks and some free agents," Pardee said. "We still have to upgrade the team, but how do you do it without any choices?

"I still think we're a contender, yes. Gosh, last Saturday was the first time we had a decent bounce of the ball in such a long time. That's about what we were away from winning-a big play or a lucky bounce. We were in every game we played this year, except the Cowboy game.

"I never felt we were in a situation where we were totally outmanned like I did the first year in Chicago. And we improved from within in Chicago and I believe we can here, too, and stay competitive."

Pardee was asked if he had a special message for the football fans of Washington.

"Well, it's a funny business," he said. "You get so high and so low. We probably weren't good enough to be 6-0. but we will be better than what we ended up in our last 10 games.

"Everybody jumps on the band-wagon after a quick start like that and now a lot of people have jumped off. They're discouraged. But we're not going to stay down. We'll be back. I know that."

Pardee declined to criticize the officiating in the Bear game, but he said films of Steve Schubert's game-winning 73-yard punt return showed two probable clips on Redskin defenders Dalls Hickman and Clarence harmon . . . Pardee spent most of his day talking with players and beginning his medical evaluation of the squad . . .