Annie's primary role is to be a source of support for Ray. She tirelessly supports Ray's endeavors of building the field and acting upon his own notion of the good. While the rest of the town looks at Ray as if he is not normal, Annie continually voices her zeal for him and what he is doing. When she says, "It's so perfect here. Do whatever you have to, to keep it that way," it is reflective of her character. The world of love that Ray finds around him starts with the love Annie gives to him.
One of the most important elements of the novel is the need to find one's voice and follow one's path regardless of external perceptions. Annie is a reminder of that as she reminds Ray that as long as he is able to act upon his own sense of self, all else will take care of itself. The harshness and coldness of the world is rebuffed with Annie, who operates as a reminder that the people in our lives that are worth hearing are those voices that remind us of who we are.
Kinsella argues that his book is about the "power of love in all directions." Annie represents this, as she unconditionally supports her husband and the quote of how perfect things are with the need to keep them that way is a reminder of this. She voices that love which ends up filling Ray's world with meaning. The "great god baseball" is secondary to the love that Ray feels towards Annie. Her function is to be the voice and face of love for Ray.