Mexican driver Sergio Perez looks set to be on his way out of McLaren after just one season with the British team.
Perez has posted an open letter on his Twitter page, thanking McLaren "for giving me the opportunity to be with them this season" and wishing the team "the very best in the future."
McLaren team principal Martin Whitmarsh says "no 2014 deal has yet been signed with any driver except Jenson (Button)."
Perez replaced Lewis Hamilton as Button's partner at McLaren and has won 35 points, failing to make a podium.
There are two races left in the 2013 season, in the United States and Brazil.