I've had apple and chicken sausage and I could see it working, but I'd saute the apples with the seasoning and onions so it's not just a big hunk of apple all by itself.

When I make a turkey I put an apple and an onion inside for flavor, along with cinnamon and some sage.

(And, yes, that is Alton Brown's recipe.)

You can make a stuffing with fruit work, but you need a separate recipe than just tossing apple into it. It makes a more sweet and savory dish instead of a hardcore savory one.