LOS ANGELES -- Chick Hearn, recovering from open heart surgery, missed the Los Angeles Lakers' game Thursday night, ending the announcer's string of consecutive games at 3,338.

The 85-year-old broadcaster received a new aortic valve during a 2½-hour operation Wednesday night. His condition was upgraded to serious but stable Thursday at Northridge Hospital Medical Center.

Hearn, who last missed a Lakers' game on Nov. 20, 1965, was replaced by Paul Sunderland on Thursday night in Houston for the Lakers' game against the Rockets.

"I'm not replacing Chick, that's the first thing people should know," Sunderland said. "I'm just filling in until Chick comes back and from all reports, his surgery went perfectly and he will fully recover and be back calling the plays."

Hearn was expected to be discharged in about a week and to be able to resume working in about six weeks, the hospital said. He was showing progress Friday morning.

"As of 9 a.m. this morning, Mr. Hearn's condition was serious but stable, and he is continuing to improve," the hospital said in a statement.

"It's going to be weird without him," color commentator Stu Lantz said. "It's the strangest feeling I've ever had in this business. It's so weird. The Lakers are playing and Chick isn't here.

"The one constant over all these years is Chick and he's not here. The players know he had surgery and they still can't believe it. They are still coming up and saying, `So Chick's not here, huh?' "

Hearn missed the 1965 game when bad weather kept him from making a flight. He has been the Lakers' only play-by-play announcer since the team moved to Los Angeles from Minneapolis at the beginning of the 1960-61 season.

Dr. Michael Soltero, who performed the surgery, said Wednesday night that about 80 percent of the blood flow through Hearn's aortic valve had been blocked, putting extra stress on his heart and leaving him fatigued.

The valve was replaced with one made of cow tissue, which Soltero said has a very good record of success.

"Chick Hearn is an icon in the city of Los Angeles and an important part of the Lakers' organization," team owner Jerry Buss said. "However, he's most important to us as a person, and our concern at this time is his health."

A member of the Basketball Hall of Fame and the American Sportscasters Hall of Fame, Hearn received a standing ovation on his birthday last month during a Lakers-Milwaukee game.