Exclusive: Boren cannot support Pelosi "in good conscience."

Rep. Dan Boren (D-OK), one of the most-conservative Democrats in the House and a member of the Blue Dog caucus, tells FOX he cannot "in good conscience support Pelosi" if she were to run for minority leader.

"I intend to support a more conservative Democratic alternative," Boren said. But Boren would not say definitively if he might back House Majority Leader Steny Hoyer (D-MD) or Rep. Heath Shuler (D-NC).

Hoyer has not signaled his intentions yet. But Hoyer holds significant support among moderate and conservative Democrats. Shuler says he would consider taking on Pelosi in a leadership contest if there were no viable alternative to the speaker.

Boren said he wasn't interested in the job himself.

Boren added that not only would he vote against Pelosi in a private meeting of the Democratic Caucus, but would oppose her on the House floor early next year when lawmakers convene to vote for Speaker.

Boren said he would not support House Minority Leader John Boehner (R-OH) for speaker, but would back another Democrat.

"I'm surprised she's considering running," Boren said of Pelosi. "She's got a little time to retire gracefully."

Boren voted for Pelosi on the House floor two years ago when Democrats unanimously re-elected her to a second term as speaker.

"I just think we need to move in a new direction," said Boren. "We can't afford to be so partisan. We could find a leader much more to the middle."

Pelosi is said to have been burning up the phone lines over the past several days, talking to members of the House Democratic Caucus. But Boren says he's not heard from Pelosi yet.