Sebastien Buemi admits he didn't expect to be axed by Toro Rosso, saying he "fell from the sky" when he was given the news.
The 23-year-old Swiss driver needs to look for a new team for 2012 after he, along with Jaime Alguersuari, was given the boot by STR on Wednesday.
Buemi started out as a Red Bull Junior driver and was handed a Toro Rosso seat at the start of the 2009 campaign.
Although he is surprised by the decision, the 23-year-old refused to say anything critical about the Faenza-based team or Red Bull Racing.
"I fell from the sky," he told Swiss paper 24 heures.
"A few days earlier I was discussing things for next season. I was in the simulator at Red Bull Racing in Milton Keynes, when Franz (Tost, Toro Rosso team principal) and Helmut (Marko, the head of the chain Red Bull Junior Team) called me... "
He added: "Yes, obviously I'm disappointed. But it is their decision and I respect it. I do not forget that without them I would never have come this far, they helped me tremendously for a long time, almost since my debut in Formula BMW (2005), then F3, GP2 and F1."
There are only a few more seats left for the 2012 season and Buemi is staying "positive and motivated".
"I can not say right now, apart from the fact that I won't be driving a Toro Rosso in 2012, but the doors are not completely closed for me at Red Bull," he said.
"For my future, there are plenty of things possible. I will stay positive and motivated."