Buddy Hardeman has a good reason for trying so hard to be ready for Dallas this week. He'd like to show the Cowboys up close and personal that he is a better player then they had figured.

That's why Hardeman, only five weeks after breaking his jaw, was in full uniform yesterday, catching punts and taking passes from Redskin quarterback Joe Theismann.

Coach Jack Pardee remains noncommittal about Hardeman's status for Sunday. Hardeman is still on the injured reserve list, and Pardee must make a decision by 4 p.m. Saturday to activate him if Hardeman is to see action against Dallas.

If it were any other opponent, Pardee likely would decide to keep Hardeman on the injured reserve list for one more week. But the temptation to activate his star kick returner-halfback for the Cowboys grows daily.

"I'm ready if they want me," Hardeman said. They really haven't talked to me about it. I'm still rusty a bit, but I feel good. I want to play, but I don't want to hurt the team."

If he does play, he'll wear a mouthpiece, something he neglected to do when he was hurt against the Steelers. And if he does play, it will fulfill a dream he has had ever since the Cowboys cut him three years ago without a tryout.

"They said my knee (from an old opertion) wasn't okay," he said. "That was ridiculous. I never have had any problems with my knee since it was fixed.

"I think they were just miffed at me because I wouldn't try out as a quarterback and I didn't jump at the chance to try out as a halfback. They seemed like they all had swelled heads, coming off a Super Bowl and all.

"I don't feel fulfilled yet this season, because I got hurt and couldn't finish. I've wanted to play in the NFL so badly for so long, if means a lot to me to come back and play."

Hardeman, a Dallas rooter as a youngster, changed his fan allegiance after making the Redskin roster this season. Once he was hurt, the club believed it had lost him until training camp, but he thought otherwise.

"I told the doc I was a quick healer," he said. "Besides, I pushed myself. I had to eat everything through a straw for three weeks, so I tossed a lot of stuff into my blender: TV dinners, steaks, pork chops. I lost only seven pounds, which I understand is good, and I've got most of them back now."

After the first week, Hardeman was bored with sitting around. To keep him from thinking about the constant pain in his jaw, he began doing light exercise, including playing racquetball. As a result, he managed to stay in reasonably good shape.

He still has braces on his teeth, but he says other than that, he has no aftereffects.

"It was a good, clean hit," he said. "It was something that can happen anytime. I understand people can be gun-shy after this, but I don't think I will be. It's never crossed my mind. All I want to do is get out there and start playing again."

The Redskins went through their most spirited practice of the season yesterday. "We accomplished in two hours what it normally would take 2 1/2 to do," Pardee said . . . Pardee was encouraged by Hardeman's play, especially after the back took a solid hit from Neal Olkewicz. "But we can't activate him until we get clearance from the doctors and we haven't got that yet," Pardee said . . . Washington will work out Saturday in Dallas, a break from its normal routine of practicing at home the day before a game. "We just want to get them used to the field," Pardee said.