Tony Stewart won't be back in a sprint car, by his own estimation, for ''a very, very long time.'' But the three-time NASCAR champion can't bear to be away from the grass-roots level of racing, and he has added another piece to his growing portfolio by acquiring the All Star Circuit of Champions Sprint Car Series - one of the oldest, traveling sprint car organizations in the country. ''My passion for sprint car racing is well known, and the All Star Circuit of Champions Sprint Car Series has been a pillar of the sport for a long time,'' Stewart said Wednesday. ''Racing is my business, and I look forward to building on the All Star Series' already impressive legacy by taking it to a new level of success and sustainability.'' Stewart broke his leg in a 2013 sprint car accident in Iowa that has had lingering repercussions on his career. More...