I'm afraid that (at least for now) wolf is not one of the possibilities. Foxes are really quite small, so I think this is unlikely, but there are two other possibilities you might need to consider. It may have been a domestic dog, remember, this "species" is quite common and comes in many shapes and colors. The other choice is the coyote. Coyotes are much more common (even in suburban areas) than most people realize. Take a close look at this picture and see if it matches the animal you saw.