Well, lookie who's got a poll out - Carl DeMaio's campaign just released the results from a poll done last week. Now, weirdly, and a bit ham-handedly, the poll did not allow people to be undecided because, and I'm quoting here:
An “undecided” option was not provided to respondents because of how the question was phrased. If the election were held today respondents would not be able to check the “undecided” box. The undecided option allows respondents to answer a question different than the one asked.
There are two problems with this poll: First, the fact that there are no "undecideds" in a poll this early in the election season is highly suspect. What happened when the respondents asked the interviewer who the candidates were? Again, at this early stage, even basic information given to the respondents could amount to push polling (where the interviewer asks questions or makes statements to get a specific result).
Second, the Republicans are way oversampled. According to the most recent data I could collect, Democrats are 41% of the San Diego City electorate, here they are 37%. Republicans are 29% of the electorate, but make up 35% of the sampling. So, this poll is going to give a slight advantage to the Republicans.
That said, as polls go, this one tells us pretty much what is conventional wisdom - that DeMaio is way ahead of the pack at 39%, that Democrats are coalescing around Filner at 28%, and that Dumanis and Fletcher are further back at 19% and 10% respectively. And remember, this poll slightly oversamples Republicans. Now, given that everyone not named Nathan Fletcher have healthy name ID, I expect Fletcher's numbers to come up at the expense of Dumanis and DeMaio. Filner is probably going to come up as well (at the expense of Dumanis, mostly), as more and more Democrats figure out who he is.