The president of CBS News, Andrew Heyward, will step down after almost 10 years in the job after failing to lift the network’s nightly news broadcast from its third-place ranking. CBS Sports President Sean McManus will take over the news division.

Mr. McManus, 50, will retain his position leading sports coverage, New York based Viacom’s CBS said in a statement yesterday. Mr. Heyward will assist with the transition and leave at the end of the year, when his contract expires.

Mr. Heyward, who turns 55 this week, is leaving a network whose newscast has posted five consecutive years of declining audiences and has trailed ABC and NBC for 13 years. Last year, CBS’s news operation, which featured newscaster Edward Murrow for 26 years, was tarnished and anchor Dan Rather stepped down after a “60 Minutes Wednesday” news report on President Bush’s military service was discredited.

Mr. McManus, son of ABC Sports announcer Jim McKay, has been president of CBS Sports since November 1996. He began his television career in 1977 at ABC Sports as a production assistant and associate producer. Mr. Mc-Manus in 1998 led CBS in acquiring the rights to National Football League games, NCAA broadcasts, and the PGA Tour, according to CBS’s Web site.

Mr. McManus also clinched the $4 billion contract to air NFL games in an effort to attract younger viewers to CBS. Adding news to Mr. McManus’s duties echoes ABC’s 1977 decision to give legendary sports TV executive Roone Arledge control of the news division. ABC broadcasters Ted Koppel and Peter Jennings at the time said ABC was making a mistake. Mr. Arledge made ABC’s “World News Tonight” the toprated evening news show.