Pete McCulley was fired and replaced by one of his assistants, Fred O-Connor, as the San Francisco 49ers changed head coaches yesterday for the fourth time in three years.

"We felt a change had to be made, and right now, not at the end of the season," said team owner Edward De-Bartolo Jr. who, General Manager Joe Thomas, decided after Sunday's 38-20 loss to the Washington Redskins that McCulley must go.

McCulley received the word yesterday from Thomas, who signed the former Redskin assistant to a three-year contract in January and said, "I believe together we can give San Francisco fans the kind of team they've been waiting for."

Instead, the 39-year-old O'Connor, offensive coordinator the past two years at Chicago, takes over a mistake-prone young team - 15 players are rookies and eight others have two years experience or less - that under McCulley, 46, was 1-8. There is no worse record in the National Football League.

Taking his dismissal stoically, McCulley said, "If Billy Martin can be fired after winning a world championship (with the New York Yankees), they could certainly let me go."

Newsmen covering the team regularly had speculated in recent days that Thomas might fire McCulley in order to take the heat off himself. Two to take the heat off himself. Two weeks ago more than 10,000 season ticket holders did not show up for a game at Candlestick Park. That followed more than 8,000 no-shows the week before.

On Saturday, Thomas became enbroiled in a barroom fight with a newsman covering the 49ers and later was physically removed from the establishment. The writer had said the 49ers "stink" and he put the blame on Thomas while defending McCulley.

McCulley started training camp in July with a veteran team but Thomas, after the season-ticket sale had been concluded, sold or cut most of the older players, including quarterback Jim Plunkett.

Season ticket sales and expectations went up when Thomas asquired O.J. Simpson in March. But Simpson, working behind a weak line and running on a knee that required surgery last year, has looked more like a ordinary running back than one of the NFL's all-time greats.

"We were not happy with the direction our program was moving," said Thomas in a terse statement.

"We've gone through a 1-8 record, after 1-3 in the preseason, and things just built up," DeBartolo said, speaking from his business office in Youngstown, Ohio. "There have been some flagrant situations that I just couldn't be easy with."

"Fred O'Connor has been made interim coach for the remainder of the season and Dan Radakovich is returning to the team as defensive coordinator," said DeBartolo, who also announced the firing of a defensive assistant, Jimmy Carr, a former Redskin.

Radakovich, who was with the Pittsburgh Steelers when they won Super Bowl titles, came to the 49ers this season but left this summer after a dispute with McCulley.