Busch admittedly "dumped" Keselowski after Keselowski got into the back of Busch's car with 31 laps remaining. Busch went on to win while Keselowski finished in 14th place.
Vice president of competition Robin Pemberton called it "good, hard racing" and said no action would be taken against either driver. He added they would keep an eye on the two in case further incidents develop.
Keselowski already is on probation for an incident involving him and Carl Edwards in the Sprint Cup race at Atlanta earlier this season.
Busch and Keselowski battled for about a dozen laps before Busch made the pass on the low side. As Busch came up the track he wasn't completely clear of the No. 22 Penske Racing driver and there was contact between the cars, sending Busch against the wall.
Busch drove back under Keselowski's left rear bumper and spun the Nationwide points leader.
"He does it to everybody else, why can't I do it to him?" Busch said of Keselowski afterwards.
Busch was booed loudly by the crowd following the race. He responded by pretending to wipe tears from his eyes after his burnout.
"I tried and tried and tried lap after lap to stay clean with Brad and I finally had him almost cleared -- yeah I slid up in front of him -- that's a slide job and then he ran into the back of me and put me in the wall," Busch said. "So, I said, 'Forget it man, you play that game and I'll play it back.' So I dumped him."
David Newton covers NASCAR for ESPN.com. He can be reached at firstname.lastname@example.org.