MOORESVILLE, N.C. - Dale Earnhardt Jr., NASCAR's most popular driver, ended months of contentious contract negotiations with his stepmother yesterday, announcing he will leave Dale Earnhardt Inc. at the end of the season because he and Teresa Earnhardt can't agree on a common vision for the family business.

"It is time for me to continue [my father's] legacy in the only way I know I can - by taking the life lessons that he told me: Be a man, race hard, and contend for championships," Earnhardt said. "That's what I intend to do, and I feel strongly that I would have my father's blessing."

Earnhardt had tried to reach a new deal with his stepmother. But the bargaining turned tense after she publicly questioned his commitment, and he later said their relationship "ain't a bed of roses."

So he'll move on, starting what should be a frenzied free-agency period that could shake the sport by causing long-term ripple effects in driver salary and sponsor deals. His sister and manager, Kelley Earnhardt Elledge, said starting their own team is an option, but is a "last choice."

He's already NASCAR's highest-paid driver, earning $20.1 million per year, a million more than No. 2 Jeff Gordon.

And the bidding has already begun.

Car owner Chip Ganassi, who lured Juan Pablo Montoya away from Formula One this season to drive one of his Dodges, openly invited Earnhardt to give him a call.

The late Dale Earnhardt started DEI in 1980 as a little company he hoped to someday hand over to his four children. DEI had grown into one of NASCAR's elite teams when Earnhardt was killed on the last lap of the 2001 Daytona 500, but it slowly has deteriorated since. The team currently fields cars for Earnhardt, Martin Truex Jr., and rookie Paul Menard.

Despite 17 career victories, Dale Earnhardt Jr. has never been a consistent championship contender. He flirted briefly with the title in 2004 but had a horrendous 2005 season, when his stepmother split up his crew and he finished a career-worst 19th in the standings.

Earnhardt rebounded slightly last season, when he made the Chase and finished fifth. He's yet to show any muscle this season, with three top-10 finishes through 10 races.

"At 32 years of age, the same age my father was when he made his final and most important career decision, it's time for me to compete on a consistent basis and contend for championships now," he said.

Earnhardt strongly believes his father's vision for DEI has been lost, and it's why he demanded 51 percent of the company during contract negotiations that started before the season began. His sister, Elledge, had set a deadline to get the deal done by the end of the month.

Although there's been speculation that Earnhardt will field his own Nextel Cup team out of JR Motorsports, his sister said it wasn't ideal.

"I believe our first choice would be to drive for another top, competitive team," Elledge said. "Our last choice would be to form our own cup team."