CHARLOTTE, N.C. — NASCAR points leader Matt Kenseth, one of the longest-tenured drivers in the series, is leaving Roush Fenway Racing at the end of the season.

He will be replaced in the No. 17 Ford – the car he has driven for all but one of his 452 career starts – by Nationwide Series champion Ricky Stenhouse Jr. and Kenseth’s long relationship with Ford will apparently come to an end. He is believed to be headed to Joe Gibbs Racing, either in Joey Logano’s No. 20 Toyota or a new Gibbs team.

Why? Good question. The team offered no answers in the sudden divorce of one of NASCAR’s longest active relationships. Only Jeff Gordon, with Hendrick Motorsports since 1993, has been with his team longer than Kenseth has been with Jack Roush.

“I’d like to thank Matt Kenseth for his many years of loyal service,” co-owner Roush said Tuesday. “Matt has been an integral part of this organization for well over a decade, and we are extremely appreciative of his accomplishments and contributions to the team, and will always consider him a part of the Roush Fenway family.”

Kenseth and teammate Greg Biffle are ranked first and second in the Sprint Cup Series, clearly poised to make a run at the championship. Kenseth opened the season with his second Daytona 500 victory, and has 11 top-10 finishes through 16 races.

Kenseth did not respond to a request for comment on Tuesday, but tweeted about his departure.

“I’m very thankful to Jack Roush for the opportunities he’s given me over the past 14 years. Together we have enjoyed a lot of success,” he posted. “And as a team we are committed as ever to the remainder of the 2012 season and chasing a 3rd sprint cup title for Jack and RFR.”

With Roush, Kenseth has built a career worthy of Hall of Fame consideration. Besides the wins at Daytona, he has won 22 Cup races overall, and the 2003 championship.

In the Nationwide Series, Kenseth has won 26 races driving for Roush.

There was speculation last weekend at Sonoma that Kenseth was leaving to join JGR, which is in a contract year with Logano. The team also has room to expand to a fourth car, and it is possible Gibbs officials are trying to move Kenseth in and keep Logano at the same time.