"I don't know why I have this view, but I don't think it's necessary to make a decision before you have to," Cochran said. "I don't have to decide today. The filing deadline is a year away. All kinds of things can happen in a year that would affect any decision I would make."

He added that he didn't want to "mislead" supporters by indicating he's in for the race when he hasn't made up his mind.

"It would be wrong to mislead people into saying I've decided I'm going to run and start raising big bucks," he said.

Cochran would be a lock for reelection if he runs again in 2014, but the 75-year-old senator is considered a top retirement risk, having served six terms.

He indicated in 2008 that he wouldn't run again. But Cochran has a comfortable position as the state's senior senator and is one of the most senior senators in the upper chamber, serving as ranking member on the Agriculture Committee and the Defense subcommittee.

Cochran's retirement would open up a competitive race, and Mississippi political observers speculate a wide slate of potential candidates could run.

Reps. Gregg Harper (R) and Alan Nunnelee (R) could run, but they'd have to resign their seats to campaign.

Other GOP contenders include Mississippi Secretary of State Delbert Hosemann, State Auditor Stacey Pickering, Lt. Gov. Tate Reeves and Mississippi House Speaker Philip Gunn. None of those office holders would have to step down to campaign.

Democrats could front Attorney General Jim Hood, former Democratic Gov. Ronnie Musgrove or U.S. Navy Secretary Ray Mabus for the seat.

Cochran's retirement would add to an already long list of Senators stepping down at the end of this session. Six Democrats and two Republicans have announced they won't be running for reelection in 2014.