Aaron Brown (search), once one of CNN's (search) most prominent anchors, is leaving the network after a shakeup that gives his prime-time slot to rising star Anderson Cooper (search) and expands it to two hours.

Cooper's old 7 p.m. EST show will be filled by an expanded version of "The Situation Room" with Wolf Blitzer, the late afternoon program attracting attention for its arresting use of multiple video screens.

With Brown left without a time slot, "we mutually looked at the lay of the land and came to this conclusion" that he would leave, said CNN/U.S. President Jon Klein.

Brown was vacationing this week, according to the network. A telephone call to his agent seeking comment was not immediately returned.

Klein said the switch was done to build CNN's schedule around what he considers its hottest personality, Cooper, and hottest new show, "The Situation Room."

Cooper, 38, has been gathering momentum all year that peaked with his on-the-scene coverage of Hurricane Katrina, Klein said.

"He's got a refreshing way of being the anti-anchor," he said. "He's not quote-unquote reporting at you. He's just being himself. He's asking the questions you would like answered. He's getting involved the way you might. You feel that he's a regular person that you can trust talking to you. He brings such a passion to the storytelling that's infectious."

After Katrina, CNN paired Cooper and Brown together in a two-hour newscast. But Klein said he had no interest in keeping them together as a team, saying "you just want to make sure that you're putting (Cooper) in the best possible situation and showcasing his talent."

Brown, 56, went to CNN from ABC in 2001 and immediately was thrust into a major role with his heartfelt anchoring following the Sept. 11 terrorist attacks. It appeared he would become the face of the network but that never really happened; he was hurt by a widely reported story in 2003 that he didn't cut short a golf outing to come to work on the day the Columbia space shuttle disintegrated.

His quirky, cerebral 10 p.m. newscast had a following, however, with fans who liked his commentaries and "The Whip," a quick review of top stories from correspondents across the globe.

It became apparent when Klein took over that he wasn't a fan, and the show's format changed dramatically with a bigger emphasis on one main story. Greta Van Susteren of Fox News Channel sharply increased her ratings advantage over CNN in the time slot this year.

The second hour of Cooper's new newscast will replace a rerun of "Lou Dobbs Tonight" that the network had been airing.