Should a raccoon be considered a serious threat to my cat?

My wife and I have noticed a raccoon who sometimes wanders through the back yard. We believe he lives in a nearby tree grove. Our cat is a very inquisitive fellow, but also very skittish and would turn heels and run at the slightest hint of danger. Since the raccoon appeared, my wife has been afraid to let the cat out. I thought that if the cat approached the raccoon, the most likely scenario would be the raccoon hissing or spitting at the cat, in which case, my cat would never approach it again. Should I be concerned of a greater possible danger?