SACRAMENTO, Calif. (Legal Newsline)-San Francisco Mayor Gavin Newsom on Friday exited the California governor's race, leaving yet-to-announce Democratic candidate Jerry Brown the only figure preparing for a run for his party's nomination.

Newsom, who has trailed Brown, the state's current attorney general in the polls and fundraising, explained his decision in a statement Friday.

"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," he said. "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."

In late September, Brown formed an exploratory committee to run for governor, a move that allows him to collect up to $25,900 in campaign cash from individual donors. Before the filing, contributors to Brown's AG campaign account were limited to $6,500 per person per election cycle.

A Field Poll released early this month showed Brown leading Newsom and the three Republicans vying for the GOP nomination. The poll indicates that Brown has a 20-point lead over Newsom, 47 percent to 27 percent, with a quarter of voters still undecided in the race for the Democratic nomination.

The poll indicates that Brown's comfortable lead over Newsom would be erased if U.S. Sen. Dianne Feinstein, D-Calif., entered the governor's race.

She has said she does not plan to run, but Allan Hoffenblum, publisher of the California Target Book, told Legal Newsline that there are rumors that Feinstein might change her mind and make another run for governor.

Republican Gov. Arnold Schwarzenegger is unable to seek reelection because of term limits. Brown, who was California governor from 1975 to 1983, held office before the term limits law was enacted, thus allowing him to run again.

Brown was the mayor of Oakland, Calif., from 1998 to 2006, before being elected as the state's chief legal officer in 2007. He unsuccessfully sought the Democratic nominations for U.S. president in 1976, 1980, and 1992.

In a statement Friday, Brown called Newsom "a talented public official" with "a bright future."

Brown added: "I am sure this was not an easy decision."

From Legal Newsline: Reach staff reporter Chris Rizo at chrisrizo@legalnewsline.com.