What could my dog have been chasing in my back yard tonight?

I have a fenced in back yard (with a few places a 10-15lb animal could get through). Currently my grass/weeds are very over grown, so I couldn't get a good view of the animal. I live in a community that is basically in the woods. When I let my dog out to use the bathroom, she started chasing an animal. It was lighter in color and it seemed to have a slender but firm tail. I'm guessing weight to be 5-8lbs. My first thought was a rabbit, but this was too slow. Definitely bigger than a squirrel. Too fast and light to be a groundhog. My dog (65lbs) could run faster, but couldn't turn as quickly. They ran around for about 20 seconds before the animal escaped through one of the small holes. It apparently knew that hole was there because the very first thing it ran for was that hole, but it missed and ended up making another circle before finding it.

My dog caught up with it a time or 2, but I don't know if she bit it or scratched it. I have seen groundhogs, deer, rabbits, squirrels and even a bobcat around here, but that's about it.

Didn't hear any hissing or growling during the chase. As far as I can tell, my dog was not hurt or scratched.

I would guess an opossum, but it didn't do the whole playing dead or make hissing noises. Any other ideas? Oh, I live in Arkansas by the Ozark Mountains.