Tim Johnson, having missed all of training camp because of a contract dispute, expected a tough first day. The Washington Redskins didn't disappoint him.

"It was a little tough today," he said. "I've been working out hitting dummies myself, but you can't simulate having pads and helmet on. I'm fighting my way through the first day. I'm not in bad shape, but it's a different feel than practicing yourself."

Johnson, 25, was acquired from the Pittsburgh Steelers Wednesday for a fourth- or fifth-round draft choice. He signed a three-year contract, began an accelerated course in Redskins football yesterday and will be in uniform and play in Saturday night's preseason game in Cleveland.

"I have to get the feel of it back," Johnson said. "There's no way to simulate the feeling of playing football without playing football. That's the biggest thing. Possibly I might play Saturday, but it's up to the coaches. There's so much to learn. It'll take time."

The Redskins are feeling considerably better about their defensive line after the arrival of 6-foot-3, 270-pound Johnson. They expect him to be an inside rusher on passing situations, but he has played both end and tackle and probably will do that this season.

"It's good to have him here," Redskins Coach Joe Gibbs said. "He comes from a good, tough football team and I like that. He played at Penn State and that gives him a good background. He's in great shape and we'll try to get him in for some running stuff Saturday."

Johnson's arrival gives the Redskins six quality defensive linemen and leaves probably one roster spot up for grabs. Rookie Kent Wells might have a slight edge because he's younger. . . .

The Redskins created a place on their 80-man roster for Johnson by placing cornerback D'Juan Francisco on waivers/injured reserve. Stokes Sits Out

Johnson could be a very valuable acquisition if end Fred Stokes's shoulder doesn't respond to strengthening therapy. Stokes won't play against Cleveland, and trainer Bubba Tyer said a decision will be made about midweek on whether he should play in the final preseason game.

The Redskins are cautiously optimistic about his recovery and say he's had much less soreness than when he first injured it. But they won't know until he gets back on the field and gets hit a couple of times. . . .

Safety Clarence Vaughn left yesterday's second practice early after bruising his left shoulder. He'll be reevaluated Friday. Short and Sweet

Gibbs said new rules designed to speed up games -- including shortening halftime from 15 minutes to 12 -- have forced him to change his schedule. "It's awful," he said. "You get in the locker room and it's time to get back out. In a place like Phoenix, where it's so far away, you'll barely have time to get inside. It used to be you used halftime to make adjustments on your game plan. That's tougher {now}."

Gibbs said he would compensate by having assistant coaches come from the press box to the sidelines earlier and that there will be more conversation during games.

He said the fact that teams are losing about 15 plays a game doesn't bother him. "If that's what they want, fine," he said. "That won't change the game. The other thing {halftime}, there's no way you can make it a better game. It'll be shorter, that's all."