(CNN) - One week after he switched races, a new poll indicates that former Rep. Tom Campbell leads the GOP field in the fight to oust Sen. Barbara Boxer of California.
According to the Field Poll, 3 in 10 people likely to vote in the Republican primary back Campbell as their party's senate nominee. That's 5 points ahead of 1 in 4 who are supporting former Hewlett Packard CEO Carly Fiorina. Six percent say they back State Assemblyman Chuck DeVore.
But the survey indicates that nearly 4 in 10 are undecided. California holds its primary on June 8. Last week Campbell gave up his bid for governor and instead jumped into the senate race.
According to the poll, Boxer, a 3-term Democrat, leads all three GOP candidates by double digits in hypothetical general election matchups.
The Field Poll was conducted January 5-17, with 958 registered voters in California questioned by telephone. The survey's overall sampling error is plus or minus 3.3 percentage points.
- CNN Deputy Political Director Paul Steinhauser contributed to this story
Follow Paul Steinhauser on Twitter: @psteinhausercnn