At a briefing Thursday with reporters, Mangano said he will take another crack at refurbishing the 77-acre Hub area through private development but declined to elaborate on the plans.
"If you want a sports-entertainment destination here in Nassau County and if you want to keep Long Island's only professional sports team, we need your help," Mangano said, calling for public support.
"If you believe in it, let's say 'Yes.' Because, if we kill it again, then we will not have it," he said.
Taxpayers in August rejected a plan to build a publicly-financed Nassau Coliseum.
Hofstra University president Stuart Rabinowitz, co-vice chairman of the Long Island Regional Economic Development Council, said earlier this week that Mangano is preparing a request for qualifications from potential developers for the Uniondale site.
Mangano said the goal of the initiative is to keep the $200 million in economic activity generated by events at the Coliseum, which would be lost if the arena closed.
But he concedes that Nassau is bumping up against a deadline.
Wang has said construction of a new arena could take 30 months. Without an anchor tenant, Mangano said an arena will not succeed.
Even under his new plan, Mangano said that getting shovels into the ground this year may be difficult: "2012 would be getting very aggressive," he said. "It's possible but aggressive. Time is definitely ticking away."
Islanders senior vice president Michael Picker did not respond to a request for comment.