Updated: July 31, 4:40 p.m.

Senate Finance negotiators have agreed to try to reach a bipartisan accord on health care reform by Sept. 15, a senior Senate source said Friday.

Chairman Max Baucus (D-Mont.) has told his Senate colleagues that at that point he would move forward with a markup of a health care bill, regardless of whether he has a bipartisan agreement to work from, sources said.

If no deal is reached, Majority Leader Harry Reid (D-Nev.) will likely attempt to move a health care bill to the Senate floor using a process, known as reconciliation, that protects the bill from filibuster. Democrats have attempted to avoid using such a process because of fears that the stringent budget rules governing reconciliation could make it difficult to pass a comprehensive bill.

Baucus has been in intense negotiations for a month with a group of six Finance Committee members including Democratic Sens. Kent Conrad (N.D.) and Jeff Bingaman (N.M.) and Republican Sens. Chuck Grassley (Iowa), Olympia Snowe (Maine) and Mike Enzi (Wyo.). But the group has not yet been able to meet any of the deadlines that Reid or President Barack Obama have attempted to set.

Reid and Obama first hoped to get a bill through the Senate before the end of next week. Then, Baucus agreed to — and Reid indicated that he expected to — mark up a bill before the August recess. But GOP push back caused Baucus to announce Thursday that no markup was imminent. However, the six negotiators pledged Thursday evening to work throughout the August recess on a possible compromise.

Jon Selib, Baucus’ chief of staff, laid out Baucus’ strategy in a meeting this week with health care stakeholders.

According to sources who were in the room, Selib said some Republicans were “killing— the health care reform effort for political gain. Selib said the bipartisan talks have yielded agreement on 95 percent of the issues, and that only two or three sticking points remain. Selib made a subtle plea to attendees at the meeting, most of them members of the business community, to urge Republicans to accept the deal, suggesting that it was the best they could hope to get.

Selib also warned the group that pursuing the reconciliation procedural tool might be necessary to get health care enacted this year, and he blamed Republicans for forcing the Democrats to seriously consider using the maneuver. Reconciliation would allow Democrats to pass a health care overhaul with a simple, 51-vote majority.

The meeting occurred before Baucus announced Thursday evening that a health care markup would not occur next week.

Meanwhile, Grassley was still lobbying against setting deadlines for an agreement, saying in a Twitter post that a few extra weeks would not hurt the process. “Little disingenuous for pres obama to say hurry up’ pass healthCare. Wk here wk there makes little differenc considerin startup is 2013,— Grassley tweeted on Friday.

Baucus’ Finance Committee spokesman declined comment.