Staten Island DA Dan Donovan is close to finally getting off the fence and declaring his intention to run for the AG office Andrew Cuomo is expected to vacate to run for governor, multiple sources confirm.

Over the past week or so, Donovan has called GOP leaders, including former Gov. George Pataki, former Mayor Rudy Giuliani, and former Reps. Susan Molinari and Bill Paxon to inform them of his decision. He also touched base with state Conservative Party Chairman Mike Long.

“He made it very clear that he’s getting serious about making a decision,” said a recipient of one of Donovan’s calls. “I would think he’s leaning heavily that way.”

It’s unclear if Donovan has touched base yet with state GOP Chairman Ed Cox. “He’s not high on the call list,” a source close to the DA said. (The two Republicans had a bit of a tiff in the media recently; Cox was speculated to be interested in keeping the AG slot open in hopes of convincing gubernatorial hopeful Rick Lazio to switch races).

Donovan will not likely formally announce his campaign until Cuomo makes his announcement and officially indicates he won’t seek re-election, a source close to the DA said.

That means you shouldn’t expect to hear anything from him until sometime around mid-May – at the earliest – since Cuomo isn’t likely to announce until right before the Democratic convention in Rye May 25-27.

Donovan has been flirting with the AG race for some time (this actually dates back to 2006 when leaders like former Sen. Alfonse D’Amato urged him to throw his hat into the ring; the party ended up with former Westchester County DA Janine Pirro, which didn’t go at all well).

The DA was worried about the cash factor, but has since received assurances that he’ll get assistance raising sufficient funds – he pegs it at between $10 million and $12 million – to run a credible campaign.

Sen. John Flanagan has been eyeing a run, too, but sources close to him say what he really wants is to run for Suffolk County executive in 2011. Now that NYC Councilman Peter Vallone Jr. has formally taken a pass on the race, it’s likely Mayor Bloomberg will back Donovan.

The Democratic field, meanwhile, is growing more crowded by the day. Liz Holtzman certainly looks like a contender. Already in the race: Sen. Eric Schneiderman, Assemblyman Richard Brodsky, attorney Sean Coffey, former state Insurance Superintendent Eric Dinallo and Nassau County DA Kathleen Rice.