NBC PLAYING MUSICAL CHAIRS WITH COMEDIES

Program notes. . . .

The NBC comedy series “Spencer” has been bounced from its Saturday night slot and will be replaced Jan. 26 by “It’s Your Move,” another first-year comedy that earlier had been bumped from its Wednesday night time period.

“It’s Your Move” will be replaced next Wednesday by “Sara,” a new comedy starring Geena Davis as a single woman who works as a legal assistance attorney in San Francisco. It will air Wednesdays at 9:30 p.m., where “It’s Your Move” premiered last fall.

“It’s Your Move,” starring Jason Bateman as a conniving teen-ager, will air Saturdays at 9:30 p.m., replacing “Spencer,” about another teen-age boy, which debuted Dec. 1. In an effort to boost the ratings for “It’s Your Move,” the producers are writing new scripts in which Bateman’s character is to be made more likable by being less of a con-man and more under the control of his mother.

As for “Spencer,” NBC said it may return to the schedule later. Speaking of ratings ploys, the syndicated soap opera “Rituals” is offering a $100,000 prize to a viewer who can figure out the details of a murder that will be committed on the show Feb. 25.

Between now and Feb. 22, the show will be offering clues as to who the victim and the murderer will be and what the motive for the killing will be. Viewers who guess all three and mail their answers to the address listed on the show will qualify for a drawing for hundreds of prizes, including vacations, a car, color TV sets and the grand prize of $100,000.

“Rituals” is seen locally on weeknights at 8:30 p.m. on KTTV Channel 11 and at 11 p.m. on XETV Channel 6.

Joining the trend of big-name performers joining the casts of the network’s prime-time serials, Ava Gardner has signed for a recurring role in CBS’ “Knots Landing.” She’ll play a woman who marries Paul Galveston (Howard Duff) and becomes stepmother to Sen. Sumner (William Devane). The first episode in which she’ll be seen is due to air Feb. 28. . . .

On “Dynasty,” meanwhile, Ali MacGraw will turn up for the first time next Wednesday, portraying a photojournalist who may be a romantic interest for Blake (John Forsythe).