The walking wounded moved gingerly at Redskin Park, where the Washington Redskins picked up the post-Dallas pieces and a wide receiver yesterday.

The Redskins placed reserve wide receiver Mark McGrath, who suffered a separated shoulder in the 31-30 loss to the Cowboys Monday night, on the injured reserve list for a minimum of four weeks yesterday. To fill his place, they signed Dave Stief, who was cut by St. Louis two weeks ago.

Stief, 27, spent five years with the Cardinals and has caught 67 passes in 68 NFL games. Big enough to play the Redskins' H-back position (motion tight end) at 6 feet 3, 195 pounds, Stief thrives on special teams. He lives in Homer, Alaska, in the offseason and, like a man in from the wilderness, said yesterday, "I didn't know for certain I'd be here till I got my plane ticket yesterday."

Health seems to be returning, though slowly, to most Redskins. Washington will play at Philadelphia Sunday, and guard Russ Grimm (slight shoulder separation) says he will play. So does strong safety Curtis Jordan, who has a terribly discolored bruised thigh and enough gumption to say, "I'm one tough Texan. No question. I'll be there Sunday."

Running back John Riggins has a jammed neck but will play, too.

Only wide receiver Alvin Garrett, who has bruised ribs, isn't certain whether he'll play against the Eagles. Although he's listed as probable, Garrett opted to keep doubts afloat, saying, "I hope I'll play. But I'm not sure."

The Redskins were both sure and healthy in the first half Monday night, when they led, 23-3, and had the Cowboys in a confused funk.

Defensive end Dexter Manley and defensive tackle Perry Brooks both sacked quarterback Danny White. Constantly harried by the Redskins' front four (ends Todd Liebenstein and Manley and tackles Darryl Grant and Dave Butz), White completed just one of nine passes for 10 yards in the first half.

Take away Tony Dorsett's 77-yard first-quarter run (which set up Dallas' only three points of the half) and the Redskins' defense--namely, the line--held the Cowboys to a total of 18 yards in their other seven running plays.

In the first half, Dallas had only 19 offensive plays. In the half, the entire Redskins' defense was tough. The defensive line was dominant.

"In the first half, their yardage (85 total yards) was damn near nil," Butz said.

Even Richie Petitbon, perfection-seeking coach of the Redskins' defense, said of the line's play in the first half Monday, "They were excellent."

In the second half, though, the defensive line slowed. "We weren't getting that pressure," said Manley.

True enough, the pressure on White slumped a great deal. He had time to throw, completing eight of 11 for 183 yards and three touchdowns. Furthermore, the Cowboys established their running game--22 carries for 88 yards in the half. In the first half, Dallas converted zero of five third-down attempts. In the second half, they converted five of seven.

What happened to the line in the second half? Manley says White took shorter steps on his dropback, giving the Redskins less time to pressure him. Grant says the Cowboys used a variety of double coverages on the line, often sliding the center over to give assistance to another offensive lineman.

Butz says the Cowboys turned cagey in the second half, steering the defensive linemen away from their mark as they moved off the ball, often by cutting under the legs of the defensive linemen.

"And they started using plays that bother a defensive line, like little trap plays," Butz said.

Lavern (Torgy) Torgeson, coach of the defensive line, said, "They started passing on rushing downs. So we couldn't get them in the situation where we could really unload (the pass rush)."

Sure enough, the Cowboys did enough things to neutralize the Redskins' pass rush. Because the Cowboys gained enough yardage on the early-down plays in the second half, they also avoided third-and-long passing situations, where 13-year veteran Tony McGee is deployed to show how he earned the nickname "Mac the Sack."

There was another factor, one that sapped strength from the defensive line in the second half.

"Speaking for myself," said Manley, "I got a little exhausted in the second half. I was trying to rush and it seemed like I was getting weaker . . . If I have to work harder now, do more running, I will."

"As time wore on, people probably got tired. Their skills probably weren't as keen," Butz said. "Our pass rush seems to be pretty good right now. We just can't have one side let up. You need a united front."

Did the Redskins have that united front in the second half? "Not like in the first half," Butz said.

Linebacker Monte Coleman, whose thigh bruise began hemorrhaging Monday morning, causing him to miss the Dallas game, was released from Sibley Hospital yesterday. Coleman is listed as doubtful for Sunday's game . . . Joe Bugel, the offensive line coach, said that if Grimm can't play Sunday (he did not play the second half against Dallas), Roy Simmons would fill in . . . Jordan and free safety Mark Murphy had a few chuckles about the impressive play made by rookie cornerback Darrell Green Monday night. Green ran across the field to catch Dorsett from behind on his 77-yard run, stopping him at the six. "Murph told me that maybe if he had had another mile and a half," Jordan said, "Dorsett would have run out of gas and maybe he could have caught him, too."