San Francisco Mayor Gavin Newsom pulled out of the California governor's race Friday in the face of blistering poll and fundraising numbers against Jerry Brown, now the last major Dem standing (and one who hasn't even officially announced his candidacy) to replace term-limited Gov. Arnold Schwarzenegger in 2010 elections.

Newsom said in a statement:

"It is with great regret I announce today that I am withdrawing from the race for governor of California. 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.

This is not an easy decision. 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.

...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."

Is Newsom really done? There's speculation that he may have stepped aside to set himself up for a lieutenant governor spot on a ticket alongside Brown. But his announcement definitely opens the door even wider for current attorney general and former Gov. Brown to waltz back into the governor's mansion -- or roller stake, as Californians like to remember the Linda Rondstat-dating governor of the late 1970s. Brown outraised Newsom nearly 7-to-1 in the first half of the year, and a Field Poll earlier this month showed Brown 20 points ahead of Newsom with Democrats (a quarter still undecided).

That poll also showed Brown, also a former mayor of Oakland, with a 31-point lead in Southern California, which seems to be out in the cold, so to speak, when it comes to the Democratic nomination. Los Angeles Mayor Antonio Villaraigosa brushed off the long-held notion that he would run for governor in a north-south showdown in June, but Newsom's withdrawal brings up new questions of whether Villaraigosa will throw his hat back into the ring. Sure, Newsom and Villaraigosa both have their Achilles' heels -- namely, respective sex scandals -- but Villaraigosa's performance in this year's mayoral race brings concerns of its own. Villaraigosa upset sitting mayor James Hahn in 2005 to become L.A.'s first Latino mayor, but this March Villaraigosa won re-election with just 55 percent of the vote in a field of unknowns -- like Walter Moore, the ultimate L.A. grass-roots candidate, who got 2.7 percent of the vote in 2005 but got 26 percent against Villaraigosa in 2009.

Even on the GOP side, though, it's still a SoCal shutout: former eBay chief executive Meg Whitman, former congressman Tom Campbell and state Insurance Commissioner Steve Poizner all hail from the Silicon Valley.