2d animation with sprite changes animated in Blender exported to Unity?

If I wanted to have a 2d animation where I have 2d sprites of the different body parts, I’m sure I can do that in blender. If I needed to change a texture (eye open/eye closed) that can easily be done as well. However, what if. Wanted to do this for a game character in Unity. Animating and exporting a 2d character should be easy. Its the texture switching that I don’t onow about. Is there a way to do that?

I am aware of the unity add-on Smooth Mooves.
http://forum.unity3d.com/threads/smooth-moves-2d-skeletal-animation.124211/

And I will use it If I need to. I was just wondering if there was a way to do this in blender and unity without needing an addon.