Deirdre Walsh
CNN Congressional Producer

House Democratic leaders are preparing to unveil a health care bill as soon as Thursday that includes a more moderate version of the public option, one that allows doctors to negotiate reimbursement rates with the federal government, several Democratic leadership aides tell CNN.

That’s a blow to Speaker Nancy Pelosi, who has argued for a more “robust” version of a the public option, one that ties reimbursement rates for providers and hospitals to Medicare rates plus a 5% increase. But Pelosi and other Democratic leaders appear to be bowing to the reality that after a week of canvassing rank and file Democrats, her preferred approach does not have enough votes. Instead the more moderate version of a public option, favored by rural and moderate Members, appears to have the most support among House Democrats.

One of these Democratic aides told CNN “the votes aren't there for robust public option, so that means we're looking at the other form of the public option.”

This aide said House Democratic leaders will meet Wednesday afternoon to make final decisions.

House Democratic leaders are planning to unveil their health care bill at a big event on the West Front of the Capitol Thursday morning. However, these sources cautioned the bill is still not final, and the event for Thursday is tentative.

“The overall message is the same as it's been at the beginning. We're committed to a bill with a public option,” one aide told CNN, arguing that the House is still presenting a strong health reform bill.

Democratic leaders expect to get a final cost estimate today from the Congressional Budget Office.

Preliminary estimates by the CBO given to leaders last week projected that a bill using either version of the public option would come in under the $900 billion cap President Obama has set for the ten year cost.

One thorny issue that must still be resolved is the final abortion language in the bill. Michigan Democrat Bart Stupak has been pushing leaders to add stronger language prohibiting the use of federal money to pay for abortions under new health care reforms. Stupak vows that if he isn’t allowed a vote on the issue he has the support of 40 anti-abortion Democrats to block the bill from getting to the House floor. Leadership aides admit they still need to find compromise wording on abortion, but are confident the issue will be resolved by the time the bill gets to the House floor.

House leaders are working to post the text of final bill on line early next week and have agreed to give Members 72 hours to read it before a vote. Under this timetable, the House would begin debating health care at the end of next week.