Jean-Eric Vergne has announced that he has been dropped by Toro Rosso for the 2015 season.
The Frenchman was expected to retain his seat alongside 17-year-old Max Verstappen, with teammate Daniil Kvyat having been promoted to parent team Red Bull as Sebastian Vettel's replacement.
However, Toro Rosso have elected to make a double change in their lineup and will reportedly name recently-crowned Formula 3.5 champion Carlos Sainz Jr as their second driver in the coming weeks.
Vergne tweeted: "Despite a good season and 22 points, I'll not drive any more for Toro Rosso in 2015. Thanks for those years. Let's go for another big challenge."
The 24-year-old finished the 2014 season 13th in the drivers' standings and with 14 more points than Kvyat.