Now is not the time to give up on a team, an offensive philosophy or a quarterback, Washington Redskins Coach Joe Gibbs said yesterday. But lose one more game, he said, and you can just about give up on a season.

"We're about reaching the end of the road here," Gibbs said. "We either get things turned around or we're going to lose this year."

The Redskins probably will have to turn it around without all-pro offensive tackle Joe Jacoby, who has missed almost four full games because of a sprained right knee. He likely will not be able to play against the New York Giants (7-3) Monday night at RFK Stadium.

The injury list provides a fitting footnote to Sunday's 13-7 loss to Dallas, a defeat that puts the Redskins (5-5) at that football point of no return:

When Gibbs was asked if Jacoby would practice Thursday (the team's first day of practice this week), he replied, "I don't know how likely that would be."

Head trainer Bubba Tyer at first said he didn't think Jacoby would be ready, then said, "Really, we'll just have to see how he does."

Gibbs said he didn't want to "rush" Jacoby back into the starting lineup, even though first-year tackle Dan McQuaid, Jacoby's replacement, yielded five sacks to defensive end Jim Jeffcoat Sunday, a Dallas team record.

Gibbs defended McQuaid yesterday.

"I thought Dan fought his guts out and did a good job . . . I do not think that was a (major) factor in the game," he said.

Jacoby could not be reached for comment yesterday, but said last week he had set no timetable for his return.

Jacoby, who is 6 feet 7 and weighs 305 pounds, twisted his knee in a practice Oct. 16 and missed the first Giants game, which the Redskins lost, 17-3.

He reinjured his knee in the second quarter of the game at Cleveland and wore a splint on his leg for several days. He has not practiced in almost three weeks.

The Redskins also are concerned about middle linebacker Neal Olkewicz, who tore his right pectoral muscle in the first quarter against the Cowboys but finished the game.

Tyer said if the medical report were being compiled yesterday (it is released Wednesday) Olkewicz would be listed as "doubtful" because of internal bleeding in his arm. "I hope he'll be ready by Monday night," Tyer said. "We've got a long time to get him ready."

For about the 10th time this season, Gibbs staunchly defended quarterback Joe Theismann, who threw three interceptions to increase his season total to 16.

"I do not think it's one person," Gibbs said.

Within the Redskins organization, Gibbs is known for standing behind his players, particularly Theismann. Although others may wonder if, at 36, Theismann has lost his ability to elude the blitz or to get the ball to a receiver who isn't wide open, Gibbs does not.

He believes that to criticize a quarterback is to lose his confidence forever, sources have said.

Gibbs realizes his is not necessarily the popular choice, especially in tough times like these.

"I still see Joe as a competitive guy," he said. "Obviously, John Riggins (also 36) and Joe Theismann have more pressure on them when they did have a bad game, or offensively, we don't do what we want to do. I think (age) is one of the things that's thrown out (as a reason).

He continued on sticking with Theismann: "Either I'm prejudiced or don't know what I'm talking about or there's something else there, which is all a possibility."

Gibbs knows the gripes.

"I can see Joe coming out of there, having a lot of great shots, nothing around him, the ball coming up short, his arm doesn't seem to have the zip, or whatever . . .

"I've got a lot more at stake in it than anybody else out there or anybody sitting here," he told reporters. "That's something I have to decide. I can also make a lot of mistakes, and have. But I'm convinced that Joe can do it."

Early turnovers, holding penalties and no big plays kill an offense, Riggins said.

"Obviously, our offense is what our problem is," he said on his show on WJLA-TV-7 last night. "We're not a great offense; we're not even a good one, I would say. Great offenses overcome penalties . . . but we get stalled."

Gibbs hinted a change might be in the works on the Riggins-George Rogers front. He said he plans to talk to both running backs to "take another bead" on their time-sharing situation.

He said he likely will not use the half-and-half formula that left him with Riggins coming in cold for a six-yard run on fourth down late in the Dallas game.

Gibbs likely will ask the league why its officials did not call an unsportsmanlike conduct penalty on the Cowboys when they had 12 men in their huddle the play before Riggins gained six yards on fourth and inches late in the game.

Safety Bill Bates entered the huddle before the Redskins' third-and-two play at their 19, then left before the snap.

CBS analyst John Madden noticed Bates and told a national television audience that having 12 players in a huddle is illegal. Bringing defenders into a huddle and then taking them out long has been a trick of some NFL teams trying to confuse offenses.

"They did it all day long," Gibbs said. "It was our understanding that you're not supposed to do that. We do protest it, but it's evidently hard for them to call."

Gibbs said he didn't tell the officials on the field but might put it in his weekly report to the league.

"I haven't had it this flagrant," he said.