Bernie Sanders Shakes Up California Campaign Staff

— -- Bernie Sanders' campaign has replaced its California state director less than a month before the state votes in its primary, according to campaign manager Jeff Weaver.

Michael Ceraso, who was the campaign's deputy director in New Hampshire, has been replaced with the campaign’s former Iowa state director, Robert Becker. Becker was sent to Michigan and New York and other key states in the last few months. He is already working in Los Angeles, campaign sources told ABC News today.

"Robert Becker is now the state director for Bernie in California,” campaign spokesman Michael Briggs said in a statement. “Becker is one of the most seasoned and savvy people working on our campaign or any campaign.”

Sanders himself has said that winning the Golden State, which holds its primary on June 7, is "imperative” to his long-shot effort to overtake rival Hillary Clinton in the race for delegates. But the change-up speaks to larger uneasiness within Sanders’ ranks ahead of the primary with the largest number of delegates at stake.

Politico first reported the shake-up.