Sen. George Voinovich (R-Ohio) will announce his retirement Monday, CNN reported on Sunday.

The longtime Ohio Republican plans to have a conference call with supporters on Monday morning to announce his decision, reportedly to be followed by a press event in the afternoon.

Voinovich’s office confirmed on Friday that he was considering ending his Senate career, but Senior Adviser Chris Paulitz did not return a request for comment on whether the moderate lawmaker planned to announce his retirement on Monday.

“For over 40 years, Sen. Voinovich has demonstrated a passion for public service,” Paulitz said in a statement on Friday. “He is thinking about the challenging situation in his beloved Buckeye State and the direction of the country as well as what is best for his family. If he changes his mind about running, he will share that decision quickly with the people of Ohio — people he considers his second family.”

The announcement would mark the third major GOP Senate retirement for the 2010 cycle, which could be encouraging news for Democrats. GOP Sens. Mel Martinez (Fla.) and Kit Bond (Mo.) already have announced they would not seek another term in two years.

But at least in Ohio, Senate Republicans can look toward a healthy recruitment bench for the seat. Among the likely candidates are former Rep. Rob Portman (R-Ohio), who stepped down from his House seat to be United States Trade Representative and later Director of the Office of Management and Budget, and former Senator Mike DeWine (R-Ohio), who lost his 2006 re-election bid.

Democrats including Lt. Gov. Lee Fisher and Rep. Tim Ryan are said to be interested in running for Voinovich’s seat. Both would be strong candidates in wake of recent Democratic gains in the state.