Senate Majority Leader Harry Reid, D-Nev., said a short-term Senate measure to keep the government running would expire on Nov. 15, rather than the Dec. 15 date included in an earlier House version of the bill.
Reid said the move would give the Senate extra time to pass complete appropriations measures.
Under the new timeline, Democrats would have more room to negotiate for a larger spending measure that replaces some of the money cut from a sequester deal aimed at reducing the nation's debt.
Democrats want to restore the cuts, saying they are hurting the poor and damaging the economy.
"The best way to stop lurching on this crisis to the next crisis is to get back into funding our government the way the Founding Fathers set it out, through the appropriations process," Reid said Tuesday.
The Senate has not passed a single appropriations bill this year.
Reid's proposal would, as expected, strip out of the budget bill a provision that would defund Obamacare. The Senate will likely vote on the funding resolution by Sunday, he said, before sending it back to the House.
The Republican-led House could approve the Senate version of the bill, clearing the way for President Obama's signature. But it is far more likely the House GOP will make changes, perhaps adding another provision that attempts to defund or delay at least part of the health care law
If Congress fails to agree on a temporary funding bill by the Sept. 30 end of the fiscal year, the federal government could shut down.
"The House is talking about changing again," Reid said, "and that is a surefire way to shut down the government."
Democrats are eager to portray the GOP as the party to blame for the failure to pass a funding measure, even though both parties disagree on a final funding resolution.
With time running out to pass a measure, both Republican and Democratic leaders said they would be willing to cut debate short, vote on the resolution and send it back to the House earlier so there is more time to hammer out a final deal.
A faction of Senate Republicans, however, is protesting the Senate bill because it will ultimately include money for the health care law.
Sen. Ted Cruz, R-Texas, and a handful of other lawmakers have been filibustering the measure — and drawing out the approval process — though rules require that they stop talking by Wednesday afternoon.
"If the House doesn't get what we send over there until Monday, they're in a pretty tough spot," Senate Minority Leader Mitch McConnell, R-Ky., said.