The Philadelphia Eagles admitted they were holding back a lot in the preseason. Perhaps not to the extent that they lost to Miami and Detroit by a combined 71-6 margin, but they said yesterday they were saving everything for the Washington Redskins.

An early onside kick and a run on a fake punt were kept under wraps for Washington, but Eagles Coach Buddy Ryan said he never planned on using the NFL's outlawed "hideout" play, having defensive end Reggie White run 70 yards for a touchdown or covering wide receivers with linebackers.

A couple of tricks worked, but in the end, blunders emanating from the unexpected led to the 34-24 loss to the Redskins at RFK Stadium.

"It's not just tricks. Buddy says, 'Hey, let's try to win games,' " said quarterback Randall Cunningham. "Those big plays are going to work for us eventually and win a game for us."

Yesterday, in a 17-second span near the close of the first half with the score 10-10, two tricks may have ultimately cost Philadelphia the game.

On fourth and 12 from Philadelphia's 43, the Eagles planned to have punter John Teltschik run for a first down. Instead, confusion led to his throwing a 36-yard pass to wide open William Frizzell on the left sideline. The play, however, turned out to be illegal.

The NFL rule book states that an offensive player may not come off the sideline and position himself less than five yards from his team's bench if teammates are nearby on the sidelines. Ryan, Frizzell and Teltschik all claimed the play was not an attempt to use what the NFL terms a "hideout" and in intramural games across college campuses nationwide is called the "sleeper play."

"We had only 10 men on the field because Russell Gary was supposed to be on, but was hurt," said Frizzell, a fourth-year free safety. "I just stepped on the field, and being I was uncovered, I was calling for the kicker to throw me the ball. After the play, the ref told me I came on the field too late."

Teltschik said he never even knew where Frizzell was.

"We always have the option to pass if a split man is wide open -- I think every team has that play," he said. "I never saw him, but the upback {Terry Hoage} heard him yelling and told me to throw it out there."

The negated gain and 15-yard penalty were not as painful as the ensuing play. Teltschik assumed the run was still on. He gained 10 yards, but Washington took over at the Eagles' 38. George Rogers scored on a one-yard run three plays later for a 17-10 Washington halftime lead.

"It was one of those deals where the run is still on until it is called off, and nobody said it was off," said Teltschik. "From the films, we knew Washington leaves the run open and, even though they made a couple of adjustments, it was still there the second time. It may have been fourth and 27, but if it works, it's the best play of the day. If it doesn't, that's what happens."

Ryan had no explanation of the failure to call off what he termed "the fiasco."

"Hell, no, I didn't think the run was still on," he said. "I didn't understand it either."

The first-half onside kick was successful, but trying to take advantage of the break, Cunningham immediately threw long for Mike Quick and was intercepted by Todd Bowles.

Throughout the game, White put enormous pressure on Washington quarterback Doug Williams although he said he was usually double- and triple-teamed. It didn't prevent him from stripping the ball from Williams and running for a touchdown that tied the game at 24 with eight seconds left in the third quarter.

"I had the ball all the way," said White, dismissing any impression the play should have been whistled dead for Williams being in the grasp of a defender. "Once I had it, I was just thinking end zone, and I knew no one was going to catch me."

The Eagles, who in recent years have prided themselves on their defense and little else, never imagined mixups that had linebackers in single coverage on wide receivers.

On one such situation, linebacker Seth Joyner was covering all-pro Art Monk on the first play of the fourth quarter. Monk easily caught a 39-yard touchdown pass from Williams to give the Redskins a lead, 31-24, they never relinquished.

"We don't cover Monk with a linebacker, but we had to because there wasn't anybody else over there," said Ryan.

"If we hadn't had the rough going early and let them throw a couple of 100-yard passes against three-deep zones and one into double coverage, we would have had a heck of a ball game. I thought we had a super effort by the kids, but losing isn't worth a damn to me."