Moonves, who will ultimately select Rather's replacement, said he believes many young viewers are turned off by a single "voice of God" anchor in the Internet age.
He spoke publicly about his search for the first time since Rather announced in late November that he was stepping down from the "CBS Evening News." Moonves stressed that he's still considering all possibilities. It's unclear whether a new format would be ready for when Rather leaves in early March, or whether an interim successor would be named.
"Those days are over when you have that guy sitting behind the desk who everyone believes to the `nth' degree," Moonves told reporters. "It's sort of an antiquated way of news telling and maybe there's a new way of doing it."
He wouldn't mention any potential participants, or comment on a Time magazine report this week that NBC's Katie Couric had been contacted to gauge her interest.
Moonves conceded the turmoil at CBS News — where three executives and a producer were fired last week for their role in an ill-fated story about President Bush's military service — has encouraged him to do something more dramatic.
So has the "CBS Evening News" status as a consistent and distant third behind NBC's "Nightly News" with Brian Williams and ABC's "World News Tonight" with Peter Jennings in the ratings, he said.
Moonves drew a parallel to "The Early Show" on CBS, which has seen ratings inch up since installing a four-person team that includes his wife, Julie Chen. When others are successful with one format, it makes sense to do something different, he said.
Nearly 30 million people watch the evening news on one of the three networks on most nights, but many of them are older. Young people tend to get their news in bits and pieces, from the Internet and cable, he said.
"We have to try and reinvent that," he said. "One of the ways we're looking at is making it younger and more relevant, something that younger people can relate to as opposed to that guy preaching from the mountaintop about what we should and should not watch."
Asked twice, Moonves wouldn't rule out a role on the evening news for Comedy Central's Jon Stewart, whose "The Daily Show" skewers politicians and the news media each night. Moonves is co-chief executive of Viacom, which owns both CBS and Comedy Central.
Except for a brief, ill-fated pairing of Rather with Connie Chung in the 1990s, evening news programs have had a single anchor for more than 20 years.
Anchor teams, like Chet Huntley and David Brinkley, are part of the evening news lore. The only real example of a multi-anchor format was when ABC News had Frank Reynolds, Peter Jennings, Max Robinson and occasionally Barbara Walters reporting from different cities from 1978 until Jennings took over alone in 1983.
The idea also likely reflects dissatisfaction with Rather's presumed heirs at CBS, John Roberts or Scott Pelley, and an absence of big names willing and able to step in.
Rather, 73, timed his departure for the March 9 anniversary that will mark 24 years since he took over from Walter Cronkite. In November, he said that his exit had nothing to do with the independent report that criticized the Bush story, which he anchored.
But Moonves said Tuesday that "I have to believe that it probably did. He had to believe that the report would come out and it would not be good."
Faced with a barrage of questions about last week's report, Moonves gave CBS News President Andrew Heyward another vote of confidence. Some critics were surprised that Heyward kept his job after the embarrassing National Guard story when four underlings were fired.
"It's been a wake-up call for us and probably everybody in the news business," Moonves said.