WASHINGTON — Senate Republicans are scrambling to reach consensus on a way to move forward with health care reform as they begin a critical weekend. A vote is expected to take place next Tuesday, but senators don't yet know whether they will be voting on a straight repeal of Obamacare, a repeal with a replacement bill or perhaps something else.

And as senators left the Capitol Thursday, Republicans appeared no closer to the 50 votes they would need to be successful in any scenario.

Failure to find enough support for a health care replacement plan delayed a vote on the bill that was planned for earlier in the week, but a renewed push to find a compromise is underway at the urging of President Donald Trump.

So far, that push has continued to run into familiar roadblocks, with moderates and conservatives unable to come to an agreement that satisfies both factions.

Related: Senate Republicans Try to Revive Health Care Bill

Even as senators continue to work on the details of the legislation in mostly informal discussions, many remain noncommittal on whether they’ll vote to even begin a Senate floor debate because they aren’t sure what the bill looks like and they fear starting a process with an unknown ending.

Senate Majority Leader Mitch McConnell said that he would bring a straight repeal to a vote after the replacement bill faltered. He has since left the door open to take up a repeal-and-replace bill, such as the latest version of the Better Care Reconciliation Act, leaving senators unsure exactly what they’ll be voting on.

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Republicans filing out of their weekly Thursday lunch were asked if they were given any clear path on what the contents of their health care votes will be. Most gave a short, one-word answer: “No.”

“I don’t even know what we’re proceeding to next week,” said Sen. Susan Collins, R-Maine.

Collins, who is opposed to both a straight repeal and the latest Senate replacement bill, said again on Thursday that she’s unlikely to vote for anything that includes major reductions in Medicaid spending.

“To do that without holding a single hearing on what the implications would be for some of our most vulnerable citizens, for our rural hospitals, for our nursing homes is not an approach I can support,” Collins said.

Sen. Rand Paul, R-Ky., who is opposed to the Senate replacement bill but supports a straight repeal of Obamacare said through a spokesman that he’s still undecided on how he’ll vote next week.

“We don’t know which bill will be brought up yet, so we can’t comment until next week,” the spokesman, Sergio Gor, told NBC News.

Leadership argues that members should vote to allow the replacement bill to be brought to the floor for debate, then they can offer amendments and help to craft a bill they like. But that brings with it political risk — members don’t want to take dozens of tough votes to possibly vote against the bill at the end and even if they bring up an amendment they like, it might not pass.

“There’s so many moving parts, I don’t know what the motion will be a part of,” said Sen. Dean Heller, R-Nev.

The path to finding 50 Republican votes was a daunting task that has been made even more difficult with the likely and unfortunate absence of Sen. John McCain, R-Ariz., who was diagnosed with an aggressive brain tumor this week after a surgery that may keep him away from Washington for an extended period of time.

At least two Republicans have said they would oppose either option currently on the table and without McCain's vote, the GOP would fall short on either, unless the replacement plan changes dramatically in the next four days.

But there are some areas to watch for potential compromise. The latest version of the replacement bill provides an additional $200 billion in savings — confirmed by the Congressional Budget Office Thursday — that could be used to pay for additional benefits and court the support of some moderates.

But that could also turn off some conservatives because that money might possibly be used as part of what’s being called a Medicaid “wraparound” to provide federal assistance to people who might lose their Medicaid in the Senate bill.

“It’s beginning to feel a little bit like a bazaar, if you will," said Sen. Bob Corker, R-Tenn. "Let’s throw $50 billion here, $100 billion there. And I’m beginning to feel that the best route forward there is just to talk about a repeal with the transition that forces the two sides together to sit down and actually pass something that will stand the test of time.”

But Sen. Rob Portman, R-Ohio, called the additional money “progress.”

Sen. Pat Roberts, R-Kan., urged all of his Republican colleagues to simply get the process started and vote to open debate on the measure.

“To improve this bill you've got to get to the bill, otherwise it’s like Thelma and Louise and we’re about to sail into the canyon and we've got to get out of the car," Roberts said. "So let's go to the bill."