From Nascar.com:

CHARLOTTE, N.C. (AP) -- Brian Vickers asked for and received permission from Hendrick Motorsports to look for a new ride, and Casey Mears was in line to replace him Thursday after informing car owner Chip Ganassi he won't be returning next year.Mears' decision comes after weeks of his steadfast claims that he wanted to extend his contract with Ganassi and was not interested in talking to other teams. Ganassi hired Mears in 2003 and stuck with him despite several mediocre seasons."I wish him well," Ganassi said. "I obviously take a lot of pleasure in the fact that I brought Casey a long way, and hopefully his next step will be as fruitful for him as his last step was."Mears is currently considered the top free agent despite never having won at any of NASCAR's levels. Kevin Harvick and Matt Kenseth both signed long-term extensions with their current teams and Dale Jarrett decided to drive a Toyota next season, leaving Mears' as the next best available driver.His departure leaves a gaping hole in Ganassi's three-car organization, which lost Jamie McMurray this year to Roush Racing. Mears was the senior driver to rookies Reed Sorenson and David Stremme, and is having the best season of his career. He's currently 13th in the points and has been in and out of the top 10 all season.Ganassi said he'll begin his search immediately for a driver for his No. 42 Dodge.

From Jayski.com: