If Congress' showdown over a government shutdown were compared to a tennis match, the ball is now on the Senate's side of the court, but not for long.

Senate Democrats on Monday are expected to reject a House-approved funding bill that would keep the government running through Dec. 15. The measure would then bounce back across the Capitol to the House just hours before the fiscal year ends and the government shuts down.

Democrats don't approve of the latest proposal from House Republicans because it would delay the implementation of Obamacare for a year and eliminate a 2.3 percent medical device tax that is expected to raise $30 billion for the program.

Senate Democrats want the House to send over a "clean" funding resolution with only revenue needed to fund the government. Democrats said they will resist any Republican efforts to diminish Obamacare, despite its lack of public support and a series of delays of the Obama administration has already ordered for parts of the law.

"Knowing full well that the Senate would reject their empty political stunts, House Republicans voted to increase the deficit, deny women coverage for critical preventative services like contraception, and deny affordable health care to millions of Americans," a spokesman for Senate Majority Leader Harry Reid, D-Nev., said Sunday.

"The Senate will do exactly what we said we would do and reject these measures," Reid's spokesman said. "At that point, Republicans will be faced with the same choice they have always faced: Put the Senate's clean funding bill on the floor and let it pass with bipartisan votes, or force a Republican government shutdown."

Republican aides tell the Washington Examiner that the House is unlikely to heed the Senate's advice. That's because House Speaker John Boehner, R-Ohio, is under intense pressure from several dozen Republicans to delay or defund Obamacare.

A top aide suggested Sunday that as the shutdown nears conservative Republicans intent on blocking Obamacare may settle for defunding just parts of the new health care law.

"Hard to see how a clean [resolution] passes at this point," the aide said. "The Democrats are going to have to accept some sort of stoppage of some aspect of Obamacare."

When the Senate sends the bill back across the Capitol Monday, the House may vote on a new funding measure that chips away at Obamacare funding without delaying most of the reforms. The measure could strike the medical device tax or eliminate the health insurance subsidies now given to members of Congress and their staffs.

Republicans and Democrats in both the House and Senate have told the Examiner that it would be difficult for Congress to reject a resolution unless at least one of those provisions are attached.

Monday could be a very long day in the Capitol, with lawmakers likely to hold late-night votes in an effort to strike a deal before midnight.

Without agreement, the government will close Tuesday due to political gridlock for the first time since January 1996, when a fight over spending between House Republicans and then-President Bill Clinton caused a 28-day shutdown.

Republicans were largely blamed for the shutdown and lost seats in the following mid-term election, though they maintained the House majority. Senate Republicans picked up two seats.

This time around, Republicans are already trying to shift the looming blame to Democrats.

About 20 House Republicans — a mix of freshmen and veterans — gathered on the Capitol steps outside the Senate late Sunday afternoon to complain that Senate Democratic leaders took the weekend off instead of working with Republicans to forge a compromise to avoid a government shutdown.

Senate Majority Leader Harry Reid, D-Nev., refused to convene the Senate on Sunday to consider the new Republican proposal because, against Reid's warnings, the new bill still targeted Obamacare. The Republicans accused Reid of deliberating pushing for a shutdown in hopes of making Republicans look bad.

"The fact that the senators aren't here, Harry Reid is off somewhere, is all the evidence you need to know that they want to shut down the government," Rep. Tim Griffin of Arkansas said.

Griffin said "high level Democrats in town" he didn't name have told him that this has been Reid's plan "for awhile."

"I personally believe that Sen. Reid and the president, for political purposes, want to shut down the government," Griffin said. "It's a scorched-earth policy. This is the old football strategy. When you get to where you want to be in a football game, you run out the clock."