Senate Majority Leader Harry Reid (D-Nev.) is racing to assemble a 60-vote coalition by Saturday, when he hopes to unveil the final legislative language and cost of the Democratic health care reform package and begin the process of ending debate.

The final changes to the $848 billion bill are to be included in what is commonly referred to as a manager’s amendment. Democratic Senators indicated Thursday that the Congressional Budget Office has begun to deliver cost estimates for key provisions of the measure.

Reid’s plan is to unveil the final package to the Democratic Conference on Saturday and file cloture on the manager’s amendment sometime after a scheduled 7:30 a.m. vote on final passage of the Defense spending bill. Under that scenario, a vote to end debate on the manager’s amendment could come as early as 1 a.m. Monday, setting in motion a series of procedural votes that would end Wednesday or Thursday, with a vote on final passage of the sweeping overhaul. However, that timeline could slip because of procedural delays, including an expected budget point of order motion.

Republicans have employed a series of tactics to slow consideration of the bill. Minority Leader Mitch McConnell (R-Ky.) said Friday: “I think we’ve made it clear we’re not going to expedite the schedule for health care. We don’t want this bill to pass and we’re going to do everything we can not to complete it.—

But it’s not just Republicans standing in the way. Moderate Sen. Ben Nelson (D-Neb.) is withholding his support for the bill pending significant changes. Given the unanimous GOP opposition to the legislation, Reid is highly unlikely to begin the cloture process absent a commitment from all 60 Democrats. Nelson appears to be the lone Democratic holdout, although other Members of the majority are claiming to be undecided.

According to a Democratic source familiar with the discussions, Nelson was negotiating with Reid and White House officials late into the night Thursday on compromises that would be satisfactory to all factions of the Democratic Conference. Nelson has vowed to filibuster the measure if it does not include language prohibiting the use of federal funds to pay for abortions, while also voicing opposition to the tax increases and proposed Medicaid expansion.

This Democratic source said Nelson is “worried— about what might be hidden in the bill. The source also indicated that Nelson views all of his concerns with the bill equally, as opposed to the widely held notion that assuaging the Nebraskan on abortion is enough to secure his vote. The source said Nelson will not support the legislation unless he’s happy with the final language.

“I think they are all relevant and they are making progress on all of them,— the Democratic source familiar with the negotiations said Friday. “Everyone is aware of the time pressure.—

Senate Health, Education, Labor and Pensions Chairman Tom Harkin (D-Iowa) said late Thursday that he expects to see a final bill Saturday and predicted that Democrats would be happy with the CBO score.

“All I can tell you is they’re good,— Harkin said of the numbers. “The only thing I’m concerned about is, the Republicans may keep us here till Christmas Day.—

If all goes according to plan, Reid would file cloture Saturday on the manager’s amendment to the health care package, the substitute amendment and the underlying bill.

Senate Democratic sources say dealing with the federal debt limit would be the last item of the year that the chamber would have to address before adjourning. Unless Republicans and Democrats can agree quickly on how to proceed, the Senate might be forced to return between Christmas and New Year’s to address it.

Jessica Brady contributed to this report.