Citing sources close to Voinovich, the cables new channel said he will announce Monday he is leaving the Senate after his second term expires in 2011. Voinovich, 72, was elected to the Senate in 1998 after serving two terms as Ohio governor.
He previously served as mayor of Cleveland from 1979-89 and represented Ohio in the U.S. House of Representatives from 1971-76.
Voinovich will be the fourth Republican to announce plans to leave the U.S. Senate in 2011, joining Kit Bond of Missouri, Mel Martinez of Florida and Sam Brownback of Kansas.
In addition, Texas Republican Sen. Kay Bailey Hutchison, whose term is to expire in 2012, is considering leaving the Senate to run for governor of Texas in 2010.