Tryson has served as Kurt Busch's crew chief at Penske Racing since midway through the 2007 season. He earned his fifth Chase berth last Saturday at Richmond, where Busch secured a spot in the playoffs with a second-place finish.

"Pat is a passionate competitor, a winner and a championship contender," team owner Michael Waltrip said in a statement. "Those were the traits we were looking for in a crew chief that would help Martin deliver on the track for [sponsor] NAPA for years to come. We couldn't be more proud to add a person of Pat's caliber to our organization."

Busch confirmed Friday at Richmond that Tryson will leave the team at season's end. It was widely rumored that he would be moving over to MWR next year to serve as Truex's crew chief. Truex will leave Earnhardt Ganassi Racing at the conclusion of this season to drive the No.56 Toyota for Waltrip.

"Michael Waltrip Racing has really come onto the scene this year and the progress they have made over a very short time is impressive," Tryson said. "Martin is a talented driver, and we'll be doing everything we can to make that happen."

Busch begins the Chase next Sunday at New Hampshire in the seventh seed. He won the inaugural Chase championship in 1994 when crew chief Jimmy Fennig guided his efforts at Roush Fenway Racing. Busch made the playoffs in '07, but did not qualify last year.