Linebacker Mel Kaufman is out of the hospital and back in the Washington Redskins' starting lineup for today's 1 p.m. game with the Philadelphia Eagles at RFK Stadium, his coaches said yesterday.

In fact, barring relapses in the pregame warmup, every injured Redskin on the roster is likely to play in this game, the first of the new, strike-threatened 1987 season.

Defensive end Dexter Manley, who partially tore a right knee ligament five weeks ago, has said privately he is ready to play. The coaches say he will not start, but likely will play in pass-rushing situations.

Running back George Rogers will start, but the key question is: How long will his sprained left big toe be able to go? Keith Griffin and Timmy Smith are waiting in the wings, as usual. The oft-injured Kelvin Bryant, who scared the Redskins when he strained his right calf muscle Thursday, will play, Coach Joe Gibbs said. Right cornerback Tim Morrison, who has a bruised right calf and ankle, can play but won't start (Barry Wilburn will), and linebacker Ravin Caldwell's abdominal strain won't prevent him from playing on special teams and in a reserve defensive role.

Kaufman, who spent Friday night at Arlington Hospital for observation after experiencing severe pain in his upper right leg, apparently had a muscle spasm in his back, perhaps caused by an inflammation of a nerve, Kaufman said. He watched practice at Redskin Park yesterday after undergoing treatment and said he still felt "a little soreness in his lower back." Linebacker coach and defensive coordinator Larry Peccatiello said Kaufman will start this afternoon.

So the Redskins' mood is upbeat, right? Wrong. Perhaps fearful of an upset, or at least a scare from an underdog, Buddy Ryan-coached team, Gibbs hardly seemed pleased with this abundance of good news.

"I feel real nervous," he said, speaking in a measured monotone. "We're still unsettled for this time of year, due to the injuries and a little bit of everything. I know how good Philly is, and I know there are a lot of things to worry about."

Gibbs, an admitted worrywart, is more concerned about the first game of a season than about a playoff game.

"The first time you go out there, you're extremely nervous about it because there's so much riding on it," Gibbs said. "To be truthful, a playoff game is more relaxing because you've gone the whole season and that's a reward for the success you've had. Let's face it, an opening loss is one of the tougher things you have to face."

Gibbs should know. His teams have lost four of six season openers and are not known for getting off to fast starts, except for last season, when they went 5-0.

In the past, they have had trouble with Philadelphia, a team of contradictions. The Eagles (1-3 in preseason, 5-10-1 last season) looked terrible in their last two preseason games, managing only a field goal a game in losing by a combined score of 71-6 to Miami and Detroit. But this is a team that beat the Redskins, 19-6, at RFK in 1985, and held a 14-0 lead in the fourth quarter of the final regular season game of 1986 before losing, 21-14. In both of those games, rangy, unpredictable Randall Cunningham was the quarterback. He will be the quarterback today, too.

Ryan says the Eagles are "light years ahead of where we were last year at this time." How light years translate to touchdowns is anyone's guess, but, last year at this time, the Redskins trounced the Eagles, 41-14, at RFK to open their successful 1986 season. Quarterback Ron Jaworski, now with Miami, played most of that game for the Eagles.

The Redskins (3-1 in preseason, 12-4 last season) and their defensive line, with or without Manley, have a dilemma. The Eagles give up sacks by the half-dozen. They set a league record by allowing 104 last season, and gave up 17 in four preseason games. But if a lineman gets too greedy and simply chases Cunningham, an elusive, 6-foot-4 scrambler, the quarterback is likely to get outside for big gains.

"He is the most elusive quarterback we will face all year," said Redskins defensive end Charles Mann.

While the Eagles offensive line has been woeful, their defensive line has been -- and still is -- spectacular. Reggie White, the left defensive end who will welcome Washington rookie right tackle Ed Simmons to the NFL this afternoon, is one of the best in the game.

"We have some plans for him, but we won't divulge them until Monday," said right guard R.C. Thielemann, who will be the man who helps Simmons if he needs it. "But it's nothing Reggie White hasn't seen before. He has been double-teamed all his life."

The Redskins expect Simmons to have some trouble with White. "I've seen all-pros have trouble with him," Thielemann said. But they also know the Eagles have juggled their secondary, moving starting free safety William Frizzell to left cornerback and Terry Hoage, a preseason backup, to the vacant free safety spot. Quarterback Jay Schroeder, who seemed to be in regular season form last week against the Los Angeles Rams, certainly will test those changes. The Redskins plan to start Glenn Dennison at H-back (man in motion), but also might use three wide receivers (Art Monk, Gary Clark and Ricky Sanders) and one tight end in some situations.

The Redskins and Eagles met in the first game last season, and now they meet again. The Redskins are starting eight players who didn't start that game a year ago; the Eagles are starting 13 different players.

It's a new season. The Eagles are hoping for different results in the opener. The Redskins aren't.