If Tom Henderson has diagnosed his knee injury correctly, the Bullets could be without their two starting guards the last 10 games of the regular season.

"The way it feels today, this is going to take a long time to heal," Henderson said yesterday. He hurt the knee in the third quarter of Friday's loss to Detroit. "I can see myself sitting out the rest of the regular season.

"I have no lateral movement and I can't push back on it. It hurts like hell. I couldn't sleep at all last night it was so bad."

Henderson's injury has been tentatively diagnosed as a "sprained knee," although Dr. Stanford Lavine, the team physician, hasn't examined it yet.

Kevin Grevey, the other starting guard, is sidelined with a pulled hamstring. His injury will be checked this week to determine when he will resume play, although he concedes he might not return until the playoffs.

Without Henderson and Grevey, Coach Dick Motta is left with only three guards: Larry Wright, Charles Johnson and Phil Chenier, who is still working toward top form after back surgery.

Johnson and Wright, both small and thin, will start against Detroit at 1:45 p.m. today in Capital Centre. Chenier will back up Johnson at the shooting guard spot while Johnson will have to spell Wright at the playmaking position.

Motta also could use either Greg Ballard or Bob Dandridge in the back court. But he said yesterday he would go with three guards.

"That should be enough," he said. "I'm really not sure how bad Tommy is hurt yet. I'm just glad we have a big lead (in the race for best record in the NBA). We just can't seem to stop these injuries."

Detroit's back court presented plenty of problems for the Bullets Friday night. Rookie John Long scored 27 points (on 27 shorts) and Kevin Porter 24 points and 12 assists in the Pistons' 124-114 triumph.

Porter and Wright match up well but Long, at 6 feet 5, has five inches on Johnson, although Chenier is just two inches shorter.

Henderson, who had just come back a week ago after recovering from a sprained ankle, was hurt during a wild 11-second segment of the third period when both Bullet coaches were ejected and five technicals were called on the club.

Henderson had just been called for a technical when he drove to the basket, tossed up a shot and tumbled to the ground. Referee Joe Crawford, who already had tossed out Motta, whistled a foul on the Bullet guard, saying he charged.

Assistant coach Arnie Bickerstaff protested so vigorously he was thrown out. Meanwhile, Henderson limped off and was replaced by Wright.

"I knew my knee was hurting but I didn't think it was bad," Henderson said. "I twisted it when I landed but I thought the pain would go away."

He came in briefly in the fourth period but quickly signaled the bench that he could not run. Afterward, the Detroit team physician checked the knee and told him he had stretched it.

Ironically, Washington had started the game with nine players after winning two games earlier in the week with just eight. Dandridge, who had been out with a sore neck, returned and scored 20 points and also picked up a technical.

Another injured Bullet, Mitch Kupchak, isn't sure he will play today. He said yesterday his sore back did not feel well Friday but was improved after a night's rest. He will decide this morning if he will suit up against Detroit.

Washington needs one victory or 76er loss to wrap up the Atlantic Division title. The Bullets also have a four-game lead over Seattle in the race for the league's top record.

As long as they are injury riddled in the back court, the Bullets will have to rely heavily on their big men to carry the team the final two weeks.

Motta also will have to hope that Chenier will be able to supply needed outside scoring if Johnson, who has shot well lately, hits one of his occasional cold streaks. Otherwise, defenses will be able to sag inside and clog the middle on Dandridge and Elvin Hayes.

"I just don't want to take a chance of not being right going into the playoffs," said Henderson, who was limping badly."With treatments and all, this could get better quicker than I think. But right now, this could be a long one."