Gary Paffett will end his role as a McLaren Formula 1 test and reserve driver after the 2014 season.
The split coincides with McLaren switch from Mercedes to Honda engines, with Paffett remaining part of the German manufacturer's factory DTM programme.
Paffett has been part of McLaren's roster since 2006, combining his F1 duties with racing in the DTM for most of that period.
"I've loved working for McLaren and hope my feedback and input over the years has been beneficial," he said.
"The engineers I've worked with have been kind enough to say that it has.
"I have many friends at McLaren, and I wish all of them the very best of luck for the future. Fingers crossed for a McLaren grand prix win or two next year!"
McLaren's acting CEO Jonathan Neale praised Paffett's contribution during his stint with the team.
"Gary has been an excellent member of the McLaren team for the best part of a decade, and his technical input, on test track and in simulator alike, has been hugely important to us," Neale said.
"Just as important, he's a great guy. We wish him well."
Paffett, the 2005 DTM champion, never got to start a grand prix during his time with McLaren, though he had been in contention for a race seat with Prodrive had its planned customer McLaren team come to fruition.
McLaren also has Oliver Turvey, who conducted the first test of its interim Honda car last week, and GP2 frontrunner Stoffel Vandoorne on its test and reserve list.