Another challenger has dropped out of the race for Noreen Evans' state Senate seat, leaving Sonoma County Supervisor Mike McGuire as the only Democrat running with two months until the filing deadline.

Novato Mayor Eric Lucan announced Wednesday that he was quitting the contest because of time constraints.

"With increasing pressures on my time, I found it was possible to run a good campaign, but not the great campaign that this large district deserves and requires," Lucan said in a statement.

The other announced candidate in the heavily-Democratic district is Republican Lawrence Weisner of Santa Rosa. He ran against Evans, who is not seeking re-election, in 2010.

Lucan said he was endorsing McGuire, whose chances to win the 2nd District Senate seat continue to improve.

Besides Lucan, Arcata resident Chris Lehman and Santa Rosa city councilwoman Erin Carlstrom have dropped out of the Senate race. Carlstrom is now running for a seat in the 10th Assembly district.