Thomas Henderson, flamboyant Cowboy linebacker, retired yesterday after Dallas Coach Tom Landry told him he was going to be placed on waivers. $"He told me I had a poor game against Washington," Henderson said at a news conference in Dallas. "When Coach Landry tells you this is the way it's going to be, that's the way it's going to be, and he usually doesn't go into details."

Asked if his decision to retire was final, the linebacker who nicknamed himself "Hollywood" said, "No, but I don't want to be passed around the league (sic)."

When Henderson announced his retirement, the Cowboys dropped plans to put him on waivers. He thus remains under contract to them in case a reconciliation is arranged. The trading deadline has passed for this season.

Gil Brandt, the Cowboy director of personnel, said last night the team had not officially informed the NFL of Henderson's status. "Right now, he's still one of our 45 on the roster," Brandt said, "but I'm sure it will be done. No, I don't think Thomas will play for us again this year."

"This is it," Landry said of the move. "Once I've done it, that it."

Under NFL rules, if the Cowboys do put Henderson on their retired list, he would not be able to play again this season. Players in that category cannot be reactivated in the last 30 days of the regular season, which ends Dec. 16.

Landry was not available for comment as to the reason for threatening to waive the contentious linebacker, but a member of the Dallas organization insisted it was because of inconsistent level of play.

"I had to be a special hero," Henderson said. I couldn't miss practice . . . I couldn't be hurt. I had to pull my load in every drill."

He said he played in the 34-20 loss to the Redskins on Sunday with a hamstring mucle pull and the flu. "I was weak at the game . . . I had chills . . . I had a virus," Henderson said, acknowledging he had a disappointing game. He was credited with no tackles.

The five-year veteran said he wouldn't have retired if Landry just benched him because "I always wanted to be remembered as a Cowboy. This is the most hollow feeling I ever had in my life. But I'm not holding a grudge . . . I'm free at last."

Henderson went on, "Coach Landry talked to me before the team meeting today and said that for a number of reasons I couldn't start for the Cowboys, and if I couldn't start, I couldn't play."

Though the 26-year-old veteran declined to be specific about those reasons, he said, "I think he (Landry) thought I was using the team for my own ventures. I expected it was going to happen one of these days. If it hadn't happened now, it would probably have happened next year, because I was going to ask for an astronomical amount of money."

The exact causes of the move remained somewhat vague. It appeared that an incident along the sidelines during the loss in Washington played in part.

While his teammates were being knocked around on the field, Henderson smiled and mugged in front of a sidelined television camera, pointing to a Dallas bandana hanging from his waist and lifting a finger into the air to signify that Dallas was still "No. 1."

As Henderson was being shown on the sideline, television announcer Pat Summerall told cohort Tom Brookshier over the air: "In our day there would probably be some disciplinary action over something like that."

When asked about the sideline incident Henderson said, "It was brought up."

Landry declined to say that the impromptu television appearance was the final straw." I was aware of it, but everything was a factor," said Landry.

Overall, he worked very hard. He would play well and then he would slip back and not be doing the job I wanted done so we would talk again . . .

"I've seen him play games as great as any linebacker I've ever seen. But there were not a lot of games like that. He had a lot of highs and lows."

Henderson, who has three years remaining on his contract, added, "I'm stable financially . . . I can live good for 10 years . . . I'm still the greatest linebacker, bar none."

Henderson, a first-round draft choice from Langston University in 1975, said he was not bitter, but added, "The Cowboys have a tradition in this sort of thing -- ask Duane Thomas or Bob Hayes or Jean Fugett."

All were traded or let go by the Cowboys.

Henderson is the subject of an interview in the January issue of Playboy magazine and is quoted as saying he thought the Cowboys had discussed "shutting him up."

Asked if the Cowboys ever tried to intimidate players, Henderson said.

"Oh, they love to intimidate you. They don't want the All-American player to change. The coach will be smiling at you one minute, screaming at you the next . . . the atmosphere is . . . everybody is so paranoid about his job, and everyone knows who's on his way out."

Henderson is cited as saying of the training camp, "It's like a military boot camp. You're making good money and your're sitting there in a schoolroom . . . and watching a projector six hours a day and being yelled at by the coaches. I'll be saying to myself, "I don't need this', so I tune them out. I never complain. I know there's no place I'd rather be than on my job."

Is there blackballing of players?

"Of course, because it's a monopoly."

Are blacks still held back in the NFL?

"No, being black is no longer an excuse. I'm proud of being black. I love it. I'm tall, talented, neat in the waist, cute in the face, and they call me "Hollywood." How can I lose?"

Henderson was asked at the news conference yesterday if he thought the Cowboys' decision was racially motivated and he said, according to the Associated Press and United Press International, "no, it was not racially motivated."