Washington Redskins Coach Joe Gibbs spent today watching game films of Atlanta's 13-10 overtime victory over the Redskins Saturday night in the preseason opener for both teams.

What Gibbs saw wasn't exactly a classic.

"Kind of on the rough edge," Gibbs said of his defending Super Bowl champions' performance. "Some of the older players were a bit rusty. Certainly, we made some mistakes on the kicking game, and of course failing to score on the goal line (on first and goal from the four) in the first half . . . It was a rough start."

Out of this preseason opener, though, came further insight into these Redskins:

Darryl Grant, starting defensive right tackle who was converted to guard 10 days ago to fill the void created by starter Mark May's injury (partially torn right triceps), has been moved back to defense.

"I wasn't comfortable on offense. I told the coaches that, and that was the basis of the decision," said Grant, who will vie with Perry Brooks for the right defensive tackle spot. Grant played guard in the second half against Atlanta, when the Falcons were sacking reserve quarterback Bob Holly five times.

"The coaches say I might go back to offense only in an emergency," Grant said.

This does not cure the depth problems of the offensive line. May will not return for another week, at the earliest. Gibbs said today rookie lineman Bob Winckler, who had been playing guard and tackle, will play only tackle now.

This leaves Don Laster, 6-foot-5, 300-pound tackle, and rookie free agent Nathan Newton to play in May's right guard spot. "We are thin at guard. Hopefully, Newt will come through for us," Gibbs said about an offensive line causing major concern.

Ken Coffey, a 23-year-old strong safety who has replaced Tony Peters (arrested last week on a cocaine trafficking charge), played the entire game against Atlanta. He intercepted one fourth-quarter pass, made several hard hits and, as Richie Petitbon, assistant coach in charge of the Redskins' defense, says, "He's got a ways to go, but he's got three games (before the opener against Dallas) to do it."

"When you replace an all-pro like Tony (Peters), there will be a little dropoff initially," Coffey said today. "I expect to start against Dallas. If I expected anything less, I'd be selling myself short."

The left cornerback spot, filled by LeCharls McDaniel, third-year Redskin, and Darrell Green, first-round draft pick from Texas A&I, is a bit more precarious. This is the position of unsigned Jeris White, a 10-year veteran who is holding out.

Some Redskins officials hope that White will return, which would allow the Redskins to break in Green slowly. General Manager Bobby Beathard has been in contact with other teams about trade possibilities and said today, "Nothing warm right now."

Atlanta quarterback Steve Bartkowski kept challenging McDaniel, who started Saturday night. For the most part, he succeeded, throwing a 16-yard touchdown pass to Alfred Jackson that gave the Falcons a 10-7 lead in the first quarter.

On his first punt return Saturday night, Green was simply marvelous. He ran Ralph Giacomarro's punt back 61 yards for the first touchdown, 1:42 into the game.

"I saw some exciting possibilities. It was like he caught, then was in the end zone in a second," said Wayne Sevier, special teams coach. Sevier was distressed with a special teams' performance that included two nine-yard punts (by Jeff Hayes and Dave Smigelsky) and a fumbled kickoff return by rookie Richard Williams, who was tackled on the Washington eight in overtime.

Green was partly responsible for a breakdown in the secondary that allowed Atlanta to win the game in overtime. Reserve quarterback Mike Moroski completed a 55-yard pass to Willie Curran, who was tackled at the Washington 12. On the the next play, Mick Luckhurst kicked the game-winning 29-yard field goal.

"We changed defenses at the line of scrimmage," Petitbon said. "Darrell played one defense, (rookie cornerback Charles) Armstead played another. Really, we can't afford to have breakdowns like that."

Reserve free safety Curtis Jordan had called an audible on the play. "I never heard it," said Green. "I just know I was in the wrong place. But I'm learning and I will only get better."

Gibbs also said to save judgement on Holly, who completed nine of 21 passes for 117 yards (one interception) after taking over the 10-10 halftime tie starter Joe Theismann had left him.

"This may be hard for people to understand, but I thought Bob Holly had a good game," said Gibbs, noting Holly stood behind an offensive line filled with rookies who could not handle Atlanta's blitzes.

The Falcons converted just two of 15 third-down plays, the Redskins seven of 18 . . . Injury update (all players are listed as day-to-day): Jacoby aggravated his lower back sprain, left guard Russ Grimm bruised his left knee, tackle Todd Hallstrom has a staph infection above his right knee, linebacker Mel Kaufman has strained muscles in his neck, linebacker Steve Booker has a sprained left ankle . . . Tickets are available for Friday night's preseason game against Cincinnati at RFK Stadium at 8 . . . Beathard said the Redskins are not interested in acquiring offensive lineman John Hannah, 32, who retired from New England but has shown interest in playing football again. "Not with the guaranteed contract he would want," said Beathard. The Redskins as a policy do not guarantee contracts. The price for Hannah would likely include two high draft picks, possibly a first- and a second-round pick.