If, as expected, Carl Edwards moves to a fourth Joe Gibbs Racing Toyota for 2015, an announcement will not come before September at the earliest, according to JGR President J.D. Gibbs.

In an exclusive interview with FOXSports.com prior to Sunday's Toyota/Save Mart 350, Gibbs also confirmed that contrary to recent rumors, sponsor M&M's will remain with Kyle Busch in the No. 18 JGR Toyota next year.

And while Gibbs did not confirm Edwards would leave Roush Fenway Racing to join JGR, he said this year represents a better chance to expand to four cars than in prior years.

Asked if it would be September before the team would make an announcement of a fourth car, Gibbs told FOXSports.com, "It would probably go at least that long, if we did anything."

On June 5, 2012, Roush Fenway said Matt Kenseth would be leaving the team at the end of that season. Kenseth's signing with JGR was made official on Sept. 12, 2012.

Asked on a scale of 1-to-100 what the likelihood of a fourth car is last year, Gibbs said, "I wouldn't put a number to it, but it's a possibility. It's just that a lot of work has to go into it."

As far as Busch and M&M's, the sponsor and driver will stay together next year, Gibbs said.

"They are," Gibbs said when asked if M&M's are signed to the No. 18 with Busch next year.

Edwards wound up winning Sunday's race at Sonoma. Afterward, he was asked if the rumors and intrigue were a distraction.

"I think you guys worry about that more than we do," he said. "We come out here and race every week and the mission is to win the championship, so for me it's really simple. I just have to give the best I can every week and that's it."