The fate of a surprise state Senate redistricting plan that has Democrats in an uproar and threatening to derail a transportation funding fix lies, for the moment, in the hands of one man: House Speaker William J. Howell.

All 100 delegates technically have a say on the bill when it comes up for a vote on the House floor, perhaps as early as Thursday. Senate Republicans muscled the measure through without notice Monday.

But in his role as speaker, Howell could very well decide the matter on his own through a procedural move. He has given little indication of how he views the bill, and most House Republicans were tight-lipped Wednesday about the way forward.

And when the matter appeared on the House calendar for the first time on Wednesday, it was quickly scuttled for the day — leading some to conclude that House Republicans were stalling.

“We’ve held it up . . . so obviously people are concerned about it,” said Del. Robert G. Marshall (R-Prince William), recalling how one of his hot-button bills was passed by last year “while they were trying to figure out ways to kill it.”

An analysis of the Republican proposal to redraw the Virginia state Senate districts.

A Republican insider who discussed the redistricting plan with multiple legislators said Wednesday that GOP delegates are concerned that the Senate’s move will kill any prospects for cooperation on the governor’s transportation agenda.

“My sense is the House is getting squishy,” said the Republican, who spoke on the condition of anonymity to be candid about internal party discussions. “These guys are freaking out. . . . I think they’d like to pass the hot potato.”

One Republican delegate who asked not to be identified said many were concerned about how their Senate GOP brethren had approved the new districts without public notice or hearings.

“I don’t think anybody signed up for this,” the delegate said. “There’s an awful lot of Republicans that are not at all happy with the situation.”

On Monday, Senate Republicans passed a House bill that called for minor “technical adjustments” to House district boundaries but amended the bill so that it also enacted sweeping changes to all of the Senate’s 40 districts. Republicans said the new maps would correct gerrymandered districts that they say Democrats pushed through in 2011 when they controlled the Senate. Democrats said the move runs afoul of the state constitution, which specifies that redistricting take place after the decennial census in years ending in 1.

The new map would create an additional majority-black district in Southside but also would make at least eight other districts more heavily Republican. The proposed districts, which require the governor’s signature and would take effect in 2015, could help Republicans make gains in the now evenly divided Senate.

As the bill comes to the House floor, opponents plan to object on the grounds that the amendment approved by the Senate was not germane to the underlying bill. Richmond operates under different rules than Washington, where all manner of things routinely get tacked onto unrelated bills. Virginia’s Capitol operates under the “single object rule,” which prohibits amendments from radically altering original bills.

The speaker has said that he would address the issue, if asked. It would be up to Howell, and Howell alone, to rule on the issue.

If he decides the amendment was not germane, the bill is dead. If he rules it is germane, the House will vote on the amended bill. If it passed, it would go to Gov. Robert F. McDonnell (R) for his signature.

Republicans have been weighing their next move and consulting lawyers who have warned staff members and legislators that they should not speak publicly because of the likelihood of litigation.

Meanwhile, Democrats have been exploring what course of legal action they would take if the bill becomes law, poring over the state constitution, a recent Richmond Circuit Court decision in a redistricting case and similar cases across the country.

On Wednesday, Del. David J. Toscano (D-Charlottesville) reminded the speaker of his options on the House floor.

“We didn’t do this,” Toscano, who is the House Democratic leader, told his fellow delegates. “They put us in a very difficult situation. I hope we can find a way to get out of it. For several reasons, it should be pretty easy for us to dispose of this bill.”

Toscano said he has not spoken to Howell about how the speaker would handle the redistricting proposal. Like others in recent days, Toscano said the move was not in the spirit of how business is done in the General Assembly.

“This interjects a level of partisanship we don’t need,” he said.

McDonnell planned on support from Democrats for his ambitious transportation funding plan, but they say the redistricting plan has ruined any chance of that.

“If they’re going to play these games with us, they should not expect our cooperation,” said Senate Minority Leader Richard L. Saslaw (D-Fairfax).

McDonnell has voiced his displeasure and frustration over the Senate’s decision on redistricting, which has shifted the conversation away from the governor’s final-session priorities of transportation and education.

“It’s an unexpected issue to have to contend with,” said McDonnell spokesman Tucker Martin. “We’re out there every day talking about transportation, education and the budget. We will deal with other legislation in due course, as it gets to us, if it gets to us.”