Washington Redskins defensive end Dexter Manley, described by Coach Joe Gibbs as being "really depressed" over the condition of his ill mother, was charged with failure to yield the right of way yesterday afternoon after his Ford Bronco ran into an 18-wheel Chevrolet tractor-trailer in front of Redskin Park and was totaled.

Manley, who apparently suffered only a minor bump on his head, was taken home by Bobby Mitchell, the Redskins' assistant general manager.

Hubert J. Bennett, the driver of the truck for the American Excelsior Co., was not injured in the accident, which took place at about 2 p.m. on Redskin Drive near Dulles International Airport, police said.

Manley is not expected to miss Sunday's game at Atlanta. When reached at home last night, he said he had a headache, but wanted to practice today. "Without a doubt," he said. "Without a doubt."

Manley, in the midst of perhaps his best season in his five years with the Redskins, alarmed the coaches when he did not report for team meetings yesterday morning.

"We were concerned about that. We were looking for him," Gibbs said.

Just before afternoon practice, Manley arrived at Redskin Park. Witnesses said he drove his 1985 vehicle through an open gate in a fence that surrounds the facility and parked it on a driveway in front of the weight room.

He walked into the weight room and walked out moments later, according to witnesses, who said he then got into his car, backed up, turned around and headed out of the parking lot.

According to Fairfax County police, Manley apparently was making a left turn out of the parking lot to go eastbound on Redskin Drive and struck the right-front fender and tire of the truck, which was westbound.

Manley's vehicle, which was hit in the left-front, was totaled, said police spokeswoman Carol Kitzerow. The truck sustained approximately $1,000 in damages, she said.

Manley passed a field sobriety test at the scene of the accident, Kitzerow said. Such a test is administered at the discretion of the police officers, she said.

Redskins head trainer Bubba Tyer said he examined Manley after the accident and said he was fine.

Manley, 26, would not elaborate on the accident. "Everything happened so quick," he said.

Bennett, 24, was delivering rolls of packing foam to Virginia Packing, a business down the street from the Redskins' offices, when the accident occurred.

"When I saw him, he was coming out flying, wide open," Bennett said. "He couldn't stop. Neither one of us could stop." Bennett estimated both his and Manley's speed at 20 to 25 mph.

Said Gibbs, "I think it was one of those things where he just was really upset and decided he would leave, got in the car and wasn't watching where he was going, really."

Gibbs spoke to Manley after the accident and later left practice for about 10 minutes to check on several accident-related matters, he said.

Manley, who ranks third in the National Football Conference in sacks with eight, has been depressed for "the last week or so," Gibbs said.

"(He) has been going through some real personal, trying times for himself. His mother's very sick . . . and he's just down now."

Manley's sister, Cynthia, called him Wednesday night and told him their mother, Jewellean, 51, has a brain tumor, Manley said.

Jewellean Manley underwent brain surgery in Houston a year ago and is unable to walk, Manley said. "The doctor says she may have to have more surgery," Manley said.

Manley's father, Carl, died in 1977 of colon cancer.

Gibbs said he would call Manley this morning at home to determine when Manley would return to practice.

"We're just trying to give him some time off," Gibbs said. "I know he's down right now. We're going to try to stay close to him and help him if we can through this . . . We gave him the afternoon off and let him go home and just go to sleep. Hopefully, he'll get rested up and be feeling better."

The accident clearly was a distraction yesterday at practice for the Redskins (4-4), who play the Falcons (1-7) Sunday at 1 p.m.

"You have 45 guys here . . . and it's not all football," Gibbs said. "As a matter of fact, there are more important things outside of football."

At practice, Steve Hamilton, a second-year player who has spent all last season and this on injured reserve, took Manley's place at right end.

It's likely the Redskins will activate Hamilton, who went on injured reserve Sept. 3 with a pinched nerve in his right shoulder, either today or Saturday, Gibbs said.

"I anticipate Dexter being okay," Gibbs said, "but Steve right now is the guy we're planning on activating."

The Redskins lost defensive tackle Darryl Grant for the season with ligament damage in his left knee in their 14-7 victory at Cleveland.

Running back John Riggins missed practice for the second day in a row with a bruised back. Gibbs said if Riggins does not practice today, "it makes it a lot less likely he will be able to play (Sunday)."

Defensive lineman Tom Beasley (pulled groin) practiced for the first time in a week. "I was really surprised he did so much," Gibbs said.