CHARLOTTE, N.C. — 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’s latest acquisition is the first racing series he owns outright. Stewart also owns Eldora Speedway in Rossburg, Ohio, and fields two World of Outlaws cars out of Tony Stewart Racing. He also is co-owner of NASCAR’s four-team Stewart-Haas Racing, which won the Sprint Cup title last season with Kevin Harvick.

His passion for sprint car racing has caused tremendous heartache over the last two years. Stewart broke his leg in a 2013 sprint car accident in Iowa that has had lingering repercussions on his career. He missed the final 15 races of the NASCAR season, has had four surgeries on his right leg and faces a fifth to remove a titanium rod at the end of this year.

He returned to a sprint car roughly 11 months after the accident and won in his first outing. But just days after the one-year anniversary of his accident, he was involved in an incident at an upstate New York dirt track in which his car struck and killed Kevin Ward Jr. as the driver walked on the track.

Stewart has said he doesn’t know if he’ll ever race a sprint car again, and he reiterated it Tuesday when asked several times if he’ll return to his first love.