CHARLOTTE, N.C. -- Kurt Busch and Penske Racing have agreed to a mutual split, the team said Monday.
The 2004 Sprint Cup champion lost favor with Penske Racing and primary sponsor Shell Pennzoil during a season in which he had multiple behavioral run-ins on and off the track.
In a statement released by the team, Busch thanked Roger Penske "for the opportunity that he has given me."
"I am grateful to Penske Racing for six very productive years," Busch said. "Together we won a lot of races -- 16 in all. Leaving a great organization and a lucrative contract is not easy, but it's an important step for me and allows me to take a deep breath to work on things that can make me a better driver and a better person."
In a video posted to his website, Busch said he had been missing the fun of racing and needed a fresh start. "Today's announcement is a positive for me," he said.
"I realized I just needed to put the fun back in racing. I needed a fresh start. Walking way from a great organization and a lucrative contract, it's not easy," he said in the video. "But it allows me to take a deep breath and work on things that can make me a better driver and a better person.''
"This is going to help me better deal with my emotions moving forward, especially those moments right outside the race car,'' Busch said in the video. "I never want to take for granted that it's a privilege to earn a living as a NASCAR driver.
"As I begin this new chapter in my life, I'm excited about the future and committed to making the changes necessary to enjoy racing again.''
Busch's future with Penske came to a head in the season finale at Homestead-Miami Speedway.
Entering the garage after his transmission failed early, Busch made an obscene gesture that happened to be in the direction of first lady Michelle Obama's motorcade.
He then had a profanity-laced tirade directed at ESPN reporter Dr. Jerry Punch and his camera crew that went viral on YouTube.
NASCAR penalized Busch $50,000. Penske officials and Shell Pennzoil publicly reprimanded him.
"While I am disappointed that Kurt will not be racing for our team in the future, both Kurt and I felt that separating at this time was best for all parties, including our team and sponsors," Penske said in the news release. "I wish Kurt the best in his future racing endeavors."
Penske was out of the country and unavailable to comment directly.
But Bud Denker, a senior vice president for Penske Corporation, said the split was best for all parties.
"Kurt had some concern with our performance,'' Denker told ESPN.com. "Obviously, we had concerns with his on and off the track behavior. We agreed to take the high road for both of us. We agreed that separating at this time was best for all parties, including Kurt and the sponsors.''
Denker would not comment on whether Penske Racing had to meet any financial obligations to Busch, who had several years left on his contract. But he said "we have no further obligations, financially or contractually.''
While team sponsor Shell Pennzoil was consulted, "it was ultimately our decision," Denker said.
"It's important for people to understand the nature of what we've done,'' Denker said. "It's a mutual separation. Kurt came to the conclusion and we have as well that it's time to move on. Kurt has been a terrific driver for us. He's a friend.
"We have been working with problems and issues in the past. It's well documented by everyone. As we looked at 2012 and beyond it was time to move on based on that incident at Homestead.''
Denker said it was a difficult decision, noting Busch has done a great job promoting sponsors for Penske Racing.
"No one is better than Kurt at hitting his mark for a sponsor,'' Denker said. "And he's performed. When you have those pieces that are part of the criteria and makeup of the driver it's very difficult to do.''
One of the criteria Shell Pennzoil had when it signed with Penske Racing last season was to have a championship-caliber driver. That prompted the move of Busch from the No. 2 Miller Lite car to the No. 22.
Denker said Busch's replacement "may not be a championship driver right now,'' but said Shell is behind anybody they choose. He acknowledged that David Ragan, who won at Daytona in July, might be a possibility.
Ragan remains under contract with Roush Fenway Racing, but he doesn't have a ride for 2012 because he lost sponsor UPS. Ragan told ESPN.com he has talked to Penske Racing president Tim Cindric to express an interest in the vacant No. 22 ride.
"It could be David, it could be others,'' Denker said. "We have not started that process yet.''
Shell also released a statement Monday.
"Shell and Pennzoil utilize our motorsports program to gain technical knowledge for our products and brands and to promote them to consumers in a positive way," the release said. "As such, we support the mutual agreement by Penske Racing and Kurt Busch to end their driver/race team relationship, effective immediately. Moving forward we will continue to work with the team at Penske Racing and to evaluate the best options for our motorsports program."
David Newton covers NASCAR for ESPN.com. He can be reached at email@example.com.