WHAT IS THIS CRITTER?

Every evening I have a visit from a small, furry creature who moves so fast I can't get a good look at him. Tonight he stopped just long enough for me to take a photo but it's mostly a blurry outline. The body is about 5" long and the hairless tail is about the same length. I think he's too small for a rat and too large for a mouse. When I chased him, he jumped from the deck into a tree and took off. Can you shed some light on this little guy for me?