Stewart undergoes third operation

Tony Stewart has undergone a third round of surgery on his injured right leg.

The three-time NASCAR Sprint Cup champion suffered a severe break to the leg in a sprint car crash in August, ruling him out of the rest of the 2013 season. 

He had two bouts of surgery in August, first to stabilize the break then to insert a metal rod. The third operation was carried out on Monday and was required to "examine and close a wound on his shin," according to a statement from his Stewart-Haas team.

The team added that it "served as a proactive measure" and would not interfere with Stewart's intention to return to racing for the start of the 2014 season.

Veteran Mark Martin is standing in for Stewart in his SHR Chevrolet.