How small was this spider? If only a few mm, there's no\t much else it could be. The spider is a male; the fuzzy 'legs'' actually are its pedipalps. And some Oecobius sp. have the thoracic disc almost entirely dark - see http://www.eurospiders.com/oecobius_sp_6379.jpg (this is a female).
I would say that this spider was about .5 inches. But my mother has stated that she has gotten a dead spider from her pool that looks like my picture but with a 1.5 - 2 inch body... and my nephew ran from two that size that were live. The large live ones were on my mother's deck in the backyard, and she lives around the corner from me. Does your guess grow that large and/or be located in California?