Jean-Eric Vergne has announced his departure from Toro Rosso.
On Twitter, the Red Bull-owned junior team's driver for the past three seasons said: "Despite a good season and 22 points, I'll not drive anymore for Toro Rosso in 2015.
"Thanks for those years. Let's go for another big challenge," the 24-year-old Frenchman added.
Speaking later to the French broadcaster Canal Plus, Vergne gave little away about his plans for 2015 and beyond.
"All I can say is that I am working very hard with a lot of people who want to help me make a good plan for 2015 and 2016," he said.
"This year, I have learned what mistakes not to repeat and so I will try to return to F1 and I think I have good chances.
"With the Toro Rosso people who said they wanted to keep me, it gave a lot of hope not only for those who believe in me but also myself," Vergne added.
It is expected that Red Bull-backed junior Carlos Sainz jr, the new Formula Renault 3.5 champion, will replace Vergne at Toro Rosso and race alongside fellow rookie Max Verstappen in 2015.