Gavin Newsom is withdrawing from California’s 2010 Governor’s race.

In a surprise announcement on Friday afternoon, the San Francisco Mayor released a statement that, “With a young family and responsibilities at city hall, I have found it impossible to commit the time required to complete this effort the way it needs to — and should be — done.”

Newsom leaves the Democratic opening without a declared candidate. Attorney General Jerry Brown has not formally announced his candidacy despite leading Newsom in the polls and in fundraising.

“This is not an easy decision,” Newsom said in the statement. “But it is one made with the best intentions for my wife, my daughter, the residents of the city and county of San Francisco, and California Democrats.”

Newsom launched his campaign more than a year ago. According to the Wall Street Journal, Newsom trailed Brown in a field poll by a 47 percent to 27 percent in the Democratic primary.

“When I embarked on this campaign in April, my goal was to engage thousands and thousands of Californians dedicated to reforming our broken system and bringing change to Sacramento,” Newsom said in the statement.

“I will continue to fight for change and the causes and issues for which I care deeply — universal health care, a cleaner environment, and a green economy for our families, better education for our children, and, of course, equal rights under the law for all citizens.”

In a statement Friday, Brown said, “Mayor Newsom is a talented public official and I believe he has a bright future.  I am sure this was not an easy decision.”

GOP gubernatorial candidate Meg Whitman’s campaign also issued a statement Friday. “Meg wishes Mayor Newsom well and looks forward to a spirited campaign against the eventual Democratic nominee.”