With the prospect of changes at several key positions, the Washington Redskins have decided to keep their starting offensive line intact for their first playoff game Jan. 9 or 10, keeping four-time Pro Bowl player Russ Grimm on the bench.

In addition, Coach Joe Gibbs said he didn't know yet if wide receiver Art Monk, a three-time Pro Bowl participant, will be ready for the playoffs. Monk suffered a partially torn knee ligament Dec. 6, and still walks with a limp.

Gibbs said the offensive line that has started the last five games, including four Washington victories, will start against either San Francisco or Chicago in the conference semifinals. This means center Jeff Bostic, who was demoted the first day of training camp because of his size to make room for Grimm at center, will retain his starting job. Grimm partially tore a knee ligament Nov. 8 and was activated for the Redskins' game at Minnesota, but did not play.

"We've got guys who've stayed together for several weeks," Gibbs said at Redskin Park. "Jeff has performed extremely well. To break that up right now I think would be a mistake. We want to keep our group together. They've been productive. We've got a good chemistry going, and when you get a good chemistry going, I don't like breaking it up."

Regarding Monk, Gibbs said, "He probably would have to start running toward the end of this week and I don't think I could say that right now. He hasn't run yet really to any extent, so I don't know. I'm not sure we could say what he's going to do right now . . . I'd say he's still a ways off."

Monk, who could not be reached for comment yesterday, probably would have to begin practicing early next week to have a chance to play in the first playoff game.

Gibbs said he will announce two other decisions Wednesday. He will name a starting quarterback, either Doug Williams or Jay Schroeder. It's considered likely he will go with Williams, who led the Redskins to 20 points in 24 minutes in a 27-24 overtime victory over the Vikings.

He also plans to decide whether to replace kicker Ali Haji-Sheikh with Jess Atkinson. Haji-Sheikh missed two of four field goals at Minnesota, although one of the two appeared to be affected by a high snap and bad hold. Gibbs said Atkinson is 100 percent healthy after suffering a dislocated left ankle in the season opener. Atkinson, who kicked for the Redskins in the final regular season game last season and in the three playoff games, has not missed a field goal or extra point with the team.

"I would not be hesitant to do it, if I thought that was the best {thing to do}," Gibbs said of replacing Haji-Sheikh.

The Redskins yesterday received more information from the NFL about when they will play, depending on the location of the game. If New Orleans defeats Minnesota in the wild-card game Sunday, the Redskins will play at San Francisco. That game would be played Jan. 9 at 4 p.m. If Minnesota wins the wild-card game, the Redskins will go to Chicago to play at 12:30 p.m. Jan. 10.

If Washington plays San Francisco, Bostic, who weighs 260 pounds, will have to go head-up on 49ers nose tackle Michael Carter, who weighs 285 pounds and is considered one of the best in the business. The Redskins took Carter and New York Giants nose tackle Jim Burt into account when they moved former guard Grimm, who weighs 275, into Bostic's spot this summer. Believing bigger was better, the Redskins amassed the largest offensive line in team history.

Now, the Redskins have changed their tune. Continuity along the line is more important than bulk, Gibbs indicated yesterday. The starters the past five weeks have been tackles Joe Jacoby and Mark May, guards R.C. Thielemann and Raleigh McKenzie and Bostic.

"Having a Russ Grimm there as a backup helps everybody," Gibbs said.

Grimm has played every position along the line in his seven seasons with the team.

The quarterback debate continued yesterday when both players took to the airwaves to discuss the situation.

"Quite naturally, I'm going to feel I should be the starting quarterback, but I thought that a couple weeks ago, too," Williams said on WUSA-TV-9. Williams replaced Schroeder when he was benched against Detroit Nov. 15, played the entire game against the Los Angeles Rams the next week, but was injured and lost the starting job when Schroeder led the Redskins to a comeback victory over the Giants.

Schroeder, appearing minutes later on WUSA, said he doesn't think "anything is wrong" with him. "We just weren't making plays . . . and we needed to shake up the offense."

Schroeder, who said after the Vikings game that he thought Williams had earned the starting job, said on television that he thought it was easier for a quarterback to come off the bench than to start a game.

"I'm not trying to have a suspense show," Gibbs said on WRC-TV-4. "I just have not seen the film yet and talked to Jay and Doug."

In a comparison of the quarterbacks' playoff performances, Schroeder looks better. In three games last season, Schroeder completed 48 of 105 passes (45.7 percent) for 469 yards, three touchdowns and two interceptions. The Redskins won two of those games.

In four playoff games with the Tampa Bay Buccaneers from 1978 to 1982, Williams completed 27 of 85 passes (31.8 percent) for 444 yards, two touchdowns and nine interceptions. The Buccaneers, generally regarded as not being as talented then as the Redskins were last season, lost three of those four games.

Patriots Top Dolphins

United Press International

MIAMI, Dec. 28 -- Steve Grogan threw a pair of first-half touchdown passes tonight to lead the New England Patriots to a 24-10 victory over the Miami Dolphins in the final regular season game of the strike-marred season.

The win marked the fifth straight time the Patriots (8-7) have beaten the Dolphins. Miami (8-7) ended the year with a loss to New England for the third straight season.

Neither team will be in the playoffs, but the Patriots' victory allowed them to finish second in the AFC East behind Indianapolis, while the Dolphins finished third.

Miami has lost its final game of every season since 1977. Box score, Page B7