NEW YORK (AP) - Nearly seven months into the launch of a new morning show, CBS said Thursday that it will replace co-host Erica Hill with chief White House correspondent Norah O'Donnell.
O'Donnell will team with Charlie Rose and Gayle King on "CBS This Morning," the third-rated morning news show behind ABC's "Good Morning America" and NBC's "Today." She'll begin the new job shortly after the Democratic and Republican national conventions are over.
CBS is taking a more serious news approach than its rivals in the morning. The new show hasn't clicked yet in the ratings, yet CBS News Chairman Jeff Fager and President David Rhodes said they were encouraged by recent positive trends.
"We just felt she was so perfect for the direction we're going in," Fager said.
O'Donnell came to CBS from NBC News in June 2011, one of Fager's first big outside hires. Besides her White House work, she's Bob Schieffer's principal substitute on "Face the Nation."
CBS' move comes a month after the "Today" show made a well-publicized switch by removing Ann Curry as co-anchor and replacing her with Savannah Guthrie. The long-dominant NBC show has plunged in the ratings this year and has been second to "GMA" since Guthrie took over. Both the ABC and NBC shows generally get about double the audience of "CBS This Morning."
O'Donnell will be starting her new job just as "Good Morning America" co-host Robin Roberts takes a medical leave. Roberts said Thursday that she will leave the show in late August or early September to undergo a bone marrow transplant. She has MDS, a blood and bone marrow disease.
Roberts will have some high-powered subs: Katie Couric, Diane Sawyer, Barbara Walters and Kelly Ripa will be among the people filling in, ABC News President Ben Sherwood said.
Hill and CBS are talking about whether she will have a future role at the network. She was the lone holdover when "CBS This Morning" was launched in January, replacing "The Early Show."
"CBS This Morning" averaged 2.47 million viewers during the first six months of the year, down from the 2.63 million that "The Early Show" was averaging during the same period last year. More recently, CBS noted that the show's viewership last week was up 7 percent over the same week in 2011.
The intense ratings struggle between its rivals this spring hasn't helped CBS in its effort to distinguish itself.
"They are trying to grow their audience at a time when both ABC and NBC are going at it 100 percent," said news consultant Andrew Tyndall of ADT Research. "They're not holding back. It's not like there's low-hanging fruit there."
A relatively slow news period has also handicapped CBS. But ratings are up for Scott Pelley's evening newscast on CBS, which has also gone in a more serious direction, raising questions about whether a breezier approach works best in the morning. It has certainly been successful for ABC.
Having Rose, who's 70, as lead anchor at a time of day when younger women dominate the available audience, could also hurt CBS, Tyndall said.
O'Donnell's hiring does not indicate any doubts about the show's direction, Fager said.
"Just the opposite," he said. "We're really confident about what we're doing. We believe it's the right thing to do for CBS News. It's what our identity is about. It's a high-quality broadcast that not only covers important stories well but also interesting stories, which is one of our trademarks. We love it. We just feel like this is a chance to make it even better."
Thursday's telecast was serious but not eat-your-spinach dry. Early in the show, reports on the Colorado shooting and Mitt Romney's trip to England were featured. Although "CBS This Morning" mentioned the Michael Jackson family problems, it had lengthy reports on a man trying to skydive from miles above the Earth, NASA's colorful new animation for its Mars exploration and an interview with the operator of the website Reddit. The last half hour featured interviews with golfer Phil Mickelson, novelist Gillian Flynn and filmmaker Jay Roach.
Continuing her White House job through the conventions will help with the transition, Rhodes said.
"It probably didn't hurt - and maybe helped - for her to stay with it as long as she has," he said.
AP Television Writer Frazier Moore in Beverly Hills, Calif., contributed to this report.