According to this article in the Milwaukee Journal Sentinel, the IndyCar race weekend will also host USAC sprints and midgets along with quarter midgets, USF2000, Star Mazda and Indy Lights.
http://www.jsonline.com/blogs/sports/111125434.html
If true, then at least one sprint race would be on pavement. Surprised that they wouldn't run the Silver Crowns on the Mile though.