MIAMI- Republican Adam Hasner, the former Florida State House Majority Leader, has formed an exploratory committee ahead of his probable run for the U.S. Senate seat currently occupied by Democratic U.S. Senator Bill Nelson who is up for reelection in 2012. GOP lawyer Cleta Mitchell has confirmed to Fox News Channel that she has been advising Hasner as he officially "tests the waters" for a senatorial run. Mitchell has previously served as legal counsel to the National Republican Senatorial Committee.

Hasner is not expected to enter into the race until the end of the month, when the first fundraising period is set to end. When he officially dives in, the Boca Raton lawyer will join Florida Senate President Mike Haridopolos in what is expected to be a growing field of GOP opponents against Nelson. Others expected to jump into the race are former U.S. Senator George Lemieux, and U.S. Congressman Connie Mack.

Despite facing ethical questions over a book he authored, Haridopolos is still seen by many Florida Republican insiders as the early favorite, and has already received the endorsement of powerful Florida lawmakers, including Florida Speaker of the House Dean Cannon & State Senator John Thrasher, the former Chairman of the Republican Party of Florida. Haridopolos is also seen as a fund-raising machine, and has already raised at least a million dollars for his campaign since he announced his bid in December of last year.

Out of the potential GOP field, Hasner has probably the closest relationship to current U.S. Senator Marco Rubio who won his seat last November, and has reinvigorated Florida's Republican party. However, a Rubio insider says that the junior senator from Florida is "not getting involved" in the 2012 GOP primary battle.

Hasner makes up part of a Republican power couple. He is married to Jilian Hasner, the campaign manager to Meg Whitman's gubernatorial campaign in California in 2010. Whitman lost to Democrat Jerry Brown.