The Washington Redskins said yesterday that linebacker LaVar Arrington's knee injury is more serious than they had thought and likely will force him to miss another four games, while starting safety Andre Lott and return specialist Chad Morton will require season-ending surgery.

Coach Joe Gibbs spent the day meeting with trainers to determine the extent of the injuries and was in contact with the NFL to dispute an officiating decision late in Sunday's 28-14 loss to the Green Bay Packers that negated what would have been a game-tying touchdown by Redskins running back Clinton Portis.

Lott tore his left pectoral muscle making a tackle Sunday and Morton tore the anterior cruciate ligament of his right knee on a kick return, becoming the latest in what has become a weekly list of serious injuries for the team.

Arrington, a three-time Pro Bowl selection who has missed the last five games after undergoing arthroscopic surgery on his right knee in late September, had a setback Oct. 25, when he pushed team trainers to allow him to return to practice. An MRI exam on Wednesday revealed a significant bone bruise on his injured knee. Bubba Tyer, the Redskins' director of sports medicine, said traces of the bone bruise were detected at the time of Arrington's original injury, but that it could have been aggravated when he slipped and fell in the practice last week.

"He needs to know the seriousness of this and he's been told this in a meeting that we had with him," Tyer said of Arrington, who all but defied the trainers to prevent him from practicing last week. "We don't want to rush it."

Arrington will have another MRI in 10 to 14 days, Tyer said, and will be held off the practice field at least that long. He will be able to ride a stationary bike and swim and must still build up the strength in the muscles around his knee before he can play. It seems unlikely that will occur this month, given the team's 2-5 record, the continued solid play by the defense and Arrington's long-term value to the franchise.

"The biggest thing is doing exactly what [the trainers] want you to do, and hope that something changes for the better," said Arrington, who added that his knee does not feel like it is getting any better. "I won't go out there and try to force the issue. I think that's what's hurt me a little bit."

Washington also may be without linebacker Mike Barrow -- a knee ailment has prevented him from playing all season -- again next Sunday, and the Redskins will immediately look to sign another safety and kick returner to replace Lott and Morton, sources said. Wide receiver James Thrash will return punts.

The secondary has been particularly depleted, with injuries forcing Lott into starting duty Sunday. Starting strong safety Matt Bowen is out for the season following knee surgery and Washington had to use journeyman safeties Todd Franz and Pat Dennis extensively against the Packers. Starting free safety Sean Taylor was suspended for the Green Bay game following his arrest on DWI charges, but he returned to practice yesterday and Gibbs said the rookie would face no further discipline from the team for his actions.

Taylor declined to speak to the media yesterday and has not spoken publicly since his arrest early last Thursday.

All of the bad news on the injury front did nothing to curb Gibbs's anger with the officiating in Sunday's game.

Gibbs was still upset yesterday about an illegal motion penalty on Thrash with less than three minutes to play and has lodged his complaints with the league.

Thrash went in motion on the play and was moving forward to set himself at the line when the ball was snapped, NFL officials informed Gibbs yesterday. Gibbs said the officials informed the Redskins that Thrash was in violation of the rulebook -- which says a player who has gone in motion must come to a full stop and cannot be moving forward before the snap.

League officials said illegal motion was a point of emphasis within the league officiating department for this season and added that game officials have called 42 illegal motion penalties through seven weeks this season, compared to six at this point a year ago.

"We don't agree with it," Thrash said after watching the play on tape yesterday, believing he had come to a stop and was correctly set on the line. "But we have to live with it."

Gibbs said Thrash moved to the right to pick up a blitzing safety and, in his estimation, did nothing illegal. Gibbs noted that the Redskins deploy that type of motion with regularity. Gibbs had team personnel send in a video of Redskins players in motion just as Thrash was on three other occasions Sunday in which no penalty was called, and he termed the officiating "inconsistent."

Moments after Thrash went in motion, quarterback Mark Brunell connected with Portis on a 43-yard touchdown pass that was negated by the penalty.

"There was nothing wrong with what we did," Gibbs said. "They'll tell you [it was illegal], maybe, but that's not what I think. We've been doing that the whole year and our entire life. That's what we do: We motion across and set to pick up a safety blitz and that's exactly what we did. . . . We do it every single time."

The overturned play was a rare long completion this season for the Redskins, whose offense sputtered again through most of Sunday's game. The offense ranks 28th overall in passing yards per game and 31st in points, while Brunell's 52.4 completion percentage is worst among NFL starters. Washington did not muster a drive of more than 31 yards until the fourth quarter against the Packers and during the first 20 minutes of the second half Brunell was 5 of 16 for 52 yards; he repeatedly overthrew open receivers on key third-down plays. "That can't happen," Brunell said.

Gibbs defended Brunell's play again yesterday and said he would start against the Detroit Lions next week. "We didn't get the ball downfield, and we weren't consistent," Gibbs said. "What's really hurt us is we haven't been able to get the ball in the end zone from a long ways out."

Brunell has completed just 37 percent of his third-down passes this season -- worst among NFL quarterbacks -- which helps explain why the Redskins are ranked 30th overall in third-down efficiency. They were 1 for 10 on third down Sunday, a trend the coaches have been trying to reverse for weeks.

Washington is the only team in the NFC yet to score 100 points this season and the team yet to reach Gibbs's weekly goal of three touchdowns in a game. They have scored just 10 total touchdowns in seven contests and been held to fewer than 20 points in each game.

Linebacker LaVar Arrington (56) has a more serious knee injury than the team had thought. Safety Andre Lott and kick returner Chad Morton need surgery.Ahman Green eludes Redskins defenders, including Khary Campbell, en route to Sunday's final touchdown.