The Penske driver was set to be on double-duty next weekend, but following his second Sprint Cup win of the season, which places him as the favorite to land one of the wildcard entries into this year's Chase, he is set to place his focus on his Cup programme in order to remain eligible for the playoff.
Keselowski basically needs to be among the top 20 in points in five-week's time in order to become a championship contender for the first time, and this weekend's race at Watkins Glen is set to place his injured ankle under massive stress, being regarded as the toughest venue for brakes.
The 27-year-old is trying to heal an avulsion fracture to his left ankle.
"Although I'm getting better, driving severely aggravates my ankle and back," wrote Keselowski on his Twitter account.
His Sprint Cup series team-mate Kurt Busch, a former Nationwide Series winner at the track, will fill in for Keselowski.
Also entered in Saturday's race is reigning Sprint Cup series champion Jimmie Johnson, who will drive for Dale Earnhardt Jr's team. He and Kurt Busch feuded following last weekend's race at Pocono.
