Busch instead wants to focus on helping the No. 22 team prepare for Saturday night's main event. Busch has failed to finish the past two Sprint Cup Series races, and has fallen from fourth to eighth in the standings.
"I thought the best opportunity for us to get our Cup program where it needed to be was to focus just 100 percent on it," Busch said.
Busch replaced Keselowski in the Nationwide race at Watkins Glen two weeks ago, and earned his first series victory since 2006.
Keselowski, the defending Nationwide champion, sat out his fifth consecutive Nationwide race Friday as he recovers from a broken ankle. Keselowski has not skipped any Cup races.
Parker Kligerman drove for Keselowski at Bristol, and Busch said putting the 21-year-old in the car was wiser than him driving.
"It made me think what the Nationwide Series is about, and that's a development program, a development series for people to work their way on up to Cup," he said.
"It's an opportunity for a young driver to try and make a name for himself and have a good run this weekend. The attention will be on him because that is a championship car, and has had a lot of big names in it this year."
Busch, like his younger brother, Kyle, is a five-time winner at Bristol and once dominated the Tennessee bullring. Kurt Busch won four of five races from 2002 through 2004, but has not been to Victory Lane here since 2006.