Updated

Stewart-Haas Racing announced on Monday that Austin Dillon will substitute for the injured Tony Stewart in the No. 14 Chevrolet this coming weekend at Michigan International Speedway.

Stewart, the three-time Sprint Cup Series champion, is sidelined indefinitely after suffering a broken right leg in a crash during a sprint car race one week ago at Southern Iowa Speedway in Oskaloosa, Iowa. The 42-year-old Stewart was released from a North Carolina hospital on Sunday following surgery to repair his fractured tibia and fibula. A metal rod was placed inside his tibia, pressing it to its atomic position.

SHR said in its news release that no timetable has been established for Stewart's return to competition.

Max Papis drove Stewart's car to a 15-place finish in Sunday's Sprint Cup race at Watkins Glen International. After missing his first event, Stewart fell from 11th to 17th in the point standings.

Dillon is the 23-year-old grandson of NASCAR multi-team owner Richard Childress and the current points leader in the Nationwide Series. He has nine Sprint Cup starts, including two at Michigan. He finished 11th there two months ago. Nationwide is running its final road course race of the season this Saturday at Mid-Ohio Sports Car Course. The 400-mile Sprint Cup event at Michigan is scheduled for Sunday.

Last month, Dillon won the inaugural Camping World Truck Series race at Eldora Speedway, a half-mile dirt track that is owned by Stewart. Dillon is the 2011 truck champion.

"I've watched Austin for many years, and at each stage of his racing career, he's been successful," Stewart said in a statement. "He's proven to be a very fast learner, and he's able to adapt quickly. Being the youngest champion in the history of the Truck Series is proof of that. His background in dirt racing is an asset, and off the track, we share many of the same interests, specifically hunting and fishing.

"I know he'll perform well at Michigan, and I'm just as confident in his ability to properly represent (No. 14 team sponsors) Mobil 1 and Bass Pro Shops throughout the race weekend."

SHR has not determined who the interim driver of the No. 14 car will be for the Aug. 24 race at Bristol Motor Speedway.