At a Capitol news conference, Rendell told reporters he hopes to meet Sunday night with top legislators, a day before procedural votes were scheduled to begin on the newly struck budget deal.
The Democrat also reeled off pointed criticisms of the deal, chiefly that its revenue projections are so unduly rosy that it would rip open a $1 billion deficit next year.
"What was done mystifies me," Rendell said. "How they think that this is real, how they think this addresses our problems. This is a get-out-of-town budget. ... I thought we were fighting for a budget that took care of our problems this year and next."
To a lesser degree, Rendell took issue with cuts in various programs for health care, student learning and financial incentives for businesses but said he felt those could be worked out by shifting the cuts to other programs.
Pennsylvania has been without a comprehensive budget since the fiscal year began July 1 and is the last state still fighting over its annual spending plan. Dividing Rendell and lawmakers has been the question of how to resolve a recession-driven, multibillion-dollar shortfall in state tax collections.
With hundreds of millions of dollars in subsidies for human services held up because of the impasse, pressure is mounting to rescue a social safety net that advocates say on the verge of a collapse that would affect hundreds of thousands of people who rely on it.
On Friday, leaders of both parties in the Senate and of the House Democratic majority caucus described the nearly $28 billion budget deal as a compromise that represents a fair middle ground.
Officials from the Senate Republican majority said Saturday they stand by the revenue projections they made in the document, which is not available to the public. It would cut spending from last year nearly 1 percent.
However, Rendell's veto threat, combined with opposition from House Republicans, may force the dealmakers to heed his demands. As currently constructed, the deal might garner the 102-vote majority needed to pass in the House, where the minority Republican party opposes it.
But a successful vote to override a gubernatorial veto would require Republican support to meet the necessary two-thirds majority, and top Republicans say they will not cooperate.
A spokesman for House Minority Leader Sam Smith, R-Jefferson, said Saturday there is no point in discussing an override vote because "the votes aren't there."
Senate Appropriations Chairman Jake Corman, R-Centre, said speculating about an override vote is getting too far ahead of the present. While the dealmakers are open to shifting spending to accommodate the governor's demands, restructuring the deal's revenue sources may be out of the question, Corman said.
"We're not going to change the deal for him," he said.
According to the dealmakers, the spending would be offset by billions of dollars in reserves and tax increases on business owners and small games of chance at private clubs, as well as revenue from newly legalized table games in casinos and more drilling for gas in state forests.
They also expect revenues to increase 0.81 percent in the current fiscal year - a judgment that Rendell said is illegal without the agreement of his budget secretary.