A close ally of Gov. Chris Christie's, veteran legislator and former state GOP chairman, state Sen. Joe Kyrillos (R-13) of Middletown has opened a U.S. Senate exploratory committee with an eye to 2012 but not limited to a candidacy against U.S. Sen. Bob Menendez (D-NJ), a source told PolitickerNJ.com.

Now commanding over $400,000 cash on hand and redistricted this year into a safer district than he represented previously, Kyrillos has long mulled a run against Menendez. Last week, he formally moved closer to a challenge when he filed with the feds and headlined a Philadelphia fundraiser, said the source.

The veteran state senator’s career in the Legislature received a boost with the 2009 victory of Christie, making him a critical liaison for the GOP administration. The governor hasn’t yet said who he would back for Senate, but if Kyrillos were eventually to decide to run he would likely be a potent Republican establishment candidate for the U.S. Senate and would have the governor’s support, said GOP sources.

The prospect of a Kyrillos run dims the likelihood of state Sen. Thomas Kean, Jr. (R-21) of Westfield getting into the field, said two Republican sources. Other 2012 GOP prospects for the Senate seat include state Sen. Michael Doherty (R-23) of Oxford and Princeton biotech millionaire John Crowley. Bergen County attorney Ian Linker is already a declared candidate.

The source close to Kyrillos made the point that the focus of the veteran senator’s exploratory committee is not narrowed to Menendez’s seat alone, and could include the senator’s consideration of the seat now occupied by U.S. Sen. Frank Lautenberg (D-NJ), who's up for re-election in 2014.

One source said the state senator intends to give himself until the end of the year to determine if he will pursue a 2012 run. The same source said President Barack Obama’s re-election chances heading into his last year and Menendez’s close ties to the president as he prepares for his own re-election bid represent factors but not the only factors for Kyrillos, who is the former N.J. state chairman of former Massachusetts Gov. Mitt Romney’s presidential campaign.

Romney is a declared 2012 candidate for president.