Good call, Scott! It is Viola pedata, Birdfoot Violet, a denizen of the dry country. It's especially at home in dry sand among a thin growth of Black Oak and Sassafras in the northern third of Indiana. Charles Deam also found it on sandstone ridges in a few counties along the southern edge of the state.
Birdfoot Violet at Ober Savanna Nature Preserve, Starke County, Indiana
The winter leaves are markedly different than those of the growing season. In winter, the leaves are coriaceous (thick and leathery), on very short petioles, usually very purple, and the lobes are short and wide. New leaves emerge in spring with long and very narrow lobes. Here's a photo of purple winter leaves and the old, withered leaves lying on the ground.