WASHINGTON (CNN) -- Barely two weeks after filing papers to set up an exploratory committee for a possible bid for the Democratic nomination in the 2008 presidential race, Sen. Evan Bayh has dropped out of the running, two Democratic sources confirmed Friday to CNN.

The sources gave no reason for Bayh's decision, but said a formal statement is expected sometime this weekend.

"At the end of the day, he concluded it wasn't the right race at the right time, given the close margin in the Senate and amount of time he would have to spend away from it to be a competitive candidate," said one of the sources.

Bayh, a Democrat from Indiana, filed papers with the FEC on Dec. 5 to form a presidential exploratory committee. That same day, he said in an interview on CNN's "The Situation Room" that he is capable of uniting Democrats, independents and Republicans in a "politics
of common purpose."

"That's not happening today," he said. "But it's something I've demonstrated repeatedly an ability to do, and it's something I think we're going to need in the next president."

Over the past year, the former two-term Indiana governor has been a constant presence in Iowa and New Hampshire -- the states that traditionally open up the official presidential campaign with a caucus and primary, respectively.

This summer, Bayh told CNN's Candy Crowley that he knew a possible run against potential candidate Hillary Clinton would be tough, but he said he felt confident in his abilities and political experience. Four Republicans -- Arizona Sen. John McCain, Kansas Sen. Sam Brownback, former Wisconsin Gov. Tommy Thompson and former New York Mayor Rudy Giuliani -- have announced the creation of exploratory committees so far. Iowa Gov. Tom Vilsack announced last month that he would seek the Democratic presidential nomination.

After serving as Indiana's governor, Bayh was elected to the Senate in 1998. He is also a former leader of the centrist Democratic Leadership Council.

-- CNN Senior Political Producer Sasha Johnson and CNN Political Editor Mark Preston