Wilbert Montgomery, the Eagles' star running back, will be in the starting lineup Sunday, Philadelphia Coach Dick Vermeil said this evening. s

But Vermeil could not predict how long Montgomery will be able to play against the Dallas Cowboys in the NFC championship game. How long he plays could decide who wins.

Philadelphia is hurting on offense. Montgomery is hobbled by leg problems, the latest of which is a sore knee. There are only two healthy wide receivers, so Vermeil says his passing offense will be limited. And his field goal kicker, Tony Franklin, has an injured ego from missing many short attempts the last month of the season.

Vermeil has little choice but to try to control the ball and hope his marvelous defense can win the game. But to control the ball, the Eagles must have a nearly healthy Montgomery. Otherwise, they are reduced to Louie Giammona as their No. 1 rusher, which is no way to run time off the clock.

"Sure, I'd like to be healthy going into this game," Vermeil said. "It's the biggest game of our lives up to this point and you'd like to have everyone at full strength. But we aren't. We'll be somewhat limited as to what we can do. That's what happens when you only have a couple of healthy wide receivers.

"I think Wilbert will do okay. Don't ask to me to tell you what the doctors say is wrong with his knee. You'd be as confused as I am. But he ran at full strength during practice today and that is a good sign."

The Philadelphia offense has been sputtering anyway, and there seems little reason to expect vast improvement Sunday. The Eagles probably will try to be conservative, limit mistakes and hope their defense can force enough Dallas turnovers to give them good field position. If they can't get into the end zone, then they'll have to hope Franklin regains his touch enough to turn those errors into field goals.

Cowboy Coach Tom Landry, however, was having none of this "poor, beaten-up" Eagle talk. "They've got their three main parts healthy, haven't they?" he asked, referring to quarterback Ron Jaworski, wide receiver Harold Carmichael and Montgomery.

"I know Montgomery is sore, but what back isn't at this stage of the season? They still all get out there and play. Heck, the last game of the season, they didn't have Montgomery or Carmichael for the final two quarters against us and they still scored something like 25 points on us. I don't see them doing anything desperate. They don't need to."

But Landry conceded that the Eagle's hopes of winning rest largely with their defense, the best in the NFC.

"Defenses usually win for you in these kinds of games," he said. "I know of only one defense that wasn't outstanding and their team still won a title. That was Philadelphia's in 1960. It was a good defense, but not extraordinary. This Eagles' defense is top-notch.

"If your defense isn't that good, it will catch up to you one of these weeks. It has to. The teams you are playing are too good not to let it."

But even Landry would have to admit that Vermeil could find himself in a bad spot Sunday. If Montgomery goes down, Giammona, the No. 3 wide receiver, would play halfback. So what if another Eagle end is hurt?

Vermeil smiled and talked about possibly employing tight end Keith Krepfle as a wide receiver. There also is Wally Henry, who was activated today. He has been sidelined after a spleen operation and Vermeil is reluctant to use him.

"It's not like he had his tonsils out," Vermeil said. And Charles Smith, usually a starter at wide receiver, has been testing his broken jaw in practice and wants to play. But again, Vermeil is hesitent.

"I don't want to risk getting him hit," Vermeil said. "I just don't think he is ready yet.

"We are just going to have to make do with the players we have."