As expected, veteran Sprint Cup driver Kurt Busch and Penske Racing announced Monday they have mutually decided to end their six-year relationship, effective immediately.

"I appreciate the victories that Kurt has brought Penske Racing and our sponsors over the past six years," team owner Roger Penske said in a statement released by the organization. "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. I wish Kurt the best in his future racing endeavors."

Busch, the 2004 Cup champion when he was employed by Roush Racing, said he did some reflecting the past couple weeks and came to the realization he needed a "fresh start."

"I am grateful to Penske Racing for six very productive years. Together we won a lot of races -- 16 in all. I'm proud that we won on a variety of tracks," Busch said in his own separate statement. "Another highlight was pushing my teammate [Ryan Newman] to a Daytona 500 win [in 2008 before Newman left Penske to go to Stewart-Haas Racing]. I also appreciate the lasting friendships I've made while working with our great sponsors through the years, including Miller Lite, Shell and Dodge."

Yet Monday's move was made in large part because Penske and Dodge officials, plus sponsors of the No. 22 car driven by Busch in 2011, had grown increasingly weary of Busch's antics in and out of the car on race weekends.

Busch, 33, recently was fined $50,000 by NASCAR for making an obscene gesture that was caught on camera as he brought his car into the garage for repairs early in the 2011 season's final race at Homestead-Miami Speedway. The fine also was for his actions as he unleashed a profanity-laced tirade on a television analyst who was seeking an interview that same day -- with those actions caught on video by a fan and posted to YouTube.

Those transgressions continued a pattern for Busch, who frequently feuded with his crew chief, Steve Addington, as well as his pit crew and even team owner Penske off and on over the past two seasons. Busch also directed verbal insults toward the Penske and Dodge engineering staffs in the garage area following the transmission problem that took him out of the race at Homestead.

Addington quit as Busch's crew chief shortly after the season ended, and was quickly hired by Stewart-Haas Racing to serve as defending Sprint Cup champion Tony Stewart's crew chief beginning next season.

Earlier during the 2011 season Busch also lost his temper and was involved in incidents with media members, for which he later apologized. He admitted more than once that he needed to do a better job of controlling his anger on race days, and just recently employed the help of a sports psychologist for that very reason.

"Coming to a mutual agreement to go our separate ways is a positive step for me," Busch said. "Over the Thanksgiving holiday I took time to reflect on what is most important to me and realized I need to find a way to put the fun back into racing. It's time for a fresh start. Leaving a great organization and a lucrative contract is not easy, but it allows me to take a deep breath and work on things that can make me a better driver and a better person."

Penske indicated he has not yet decided who to put in the No. 22 in the Cup Series and Busch is unsure where he will drive next season. But both parties clearly are ready to move on.

"I recognize the passion and emotion that have helped me succeed on the track need to be better channeled off the track," Busch said. "The past few months I began working with a sports psychologist to help me better deal with my emotions, especially following moments of frustration during competition.

"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 career, I'm excited about the future and committed to making the changes necessary for me to enjoy racing again, to compete for championships and to better represent NASCAR, my sponsors, my team and my fans."

Busch began driving for Penske in 2006 and has won at least one race in each of his six seasons with the organization -- and in each of the past 10 Cup seasons overall. He has 24 career victories in points races, including two last season -- one of which came at Dover early in the just-concluded Chase for the Sprint Cup. He ended the 2011 season with three poles, eight top-five and 16 top-10 finishes in addition to the two wins.

But Busch faded down the stretch in the Chase and finished 11th in points after he and team officials had hoped he would contend for the championship.

Busch spent his first five Cup seasons with the organization then known as Roush Racing, winning a championship in 2004. Eventually his relationship with team owner Jack Roush and others within that organization soured, however, and he was forced out of his job there toward the end of the 2005 season when a team official stated the organization would "no longer be Kurt Busch's apologist."

The top candidates to replace Busch in the No. 22 car appear to be David Ragan, who lost his ride at Roush Fenway Racing at the end of last season; and Sam Hornish, Jr., a long-time Penske driver both in NASCAR and IndyCar who already is slated to run a full-time Nationwide Series schedule for the organization next season. Another possible candidate would be David Reutimann, who recently lost his ride at Michael Waltrip Racing.

It is unknown at this point where Busch will land, although he almost certainly will be offered another job somewhere in the Cup garage after making the Chase in four of the past five seasons and finishing as high as fourth in 2009. By agreeing to part ways mutually, it is believed that Busch is forfeiting at least a large portion of the approximately $40 million in salary he was scheduled to receive over the final four years of a five-year contract extension he had signed in April of 2010. Both parties said at the time that they believed the extension would keep Busch employed by Penske Racing through the 2015 season.

That ended up being wishful thinking, although Busch expressed optimism Monday that he was leaving on better terms than it obviously appears to outside observers of the split that was unexpected as recently as two months ago -- and uncertain even after what happened at Homestead.

"I want to personally thank Roger Penske for the opportunity he gave me and for his friendship, which will continue long into the future," Busch said.