According to paddock speculation, both Sebastien Buemi and Jaime Alguersuari have reached only 'verbal agreements' to keep racing with Toro Rosso in 2011.
After boss Franz Tost said recently the duo are re-confirmed for next season, the young drivers both indicated it is possible they will in fact not be racing a Faenza-built car in 2011.
"The team confirmed its intention to continue with me and I am very happy," Swiss Buemi, 21, is quoted by Auto Hebdo at Hockenheim.
He has been linked with a move to Renault in 2011.
"It's normal that there has been some discussions elsewhere, but for me, the situation has always been more or less clear," added Buemi, who like Alguersuari is believed to be contracted to team owner Red Bull, not Toro Rosso.
Pressed about his Toro Rosso situation, he said: "In life, everything can change quickly, but for the moment, that's the way it is.
"Right now, my goal is to do well and prove that I deserve to be with a team that can win races. I'll try to make the most of my time with Toro Rosso.
"This is the team I started with and I want to show we can do great things with a small budget," added Buemi.
Spain's Marca sports newspaper quotes 20-year-old Alguersuari as saying Tost's confirmation of his seat for 2011 is "an extra motivation".
"But I'm not thinking about that because so many things can happen, both on the good side and the bad side," the Spaniard said at Hockenheim.
Alguersuari dodged a question about whether there have been talks with other teams.
"I don't know, I'm not thinking about it. I'm happy where I am and confident for the rest of the season. We'll see," he answered.
He said Toro Rosso is under pressure to keep up with the other established teams.
"We have had four races without improvement, and both Force India and Williams have overtaken us because they have greater capacities to develop.
"Our car is just as good, but our development rate is lower," added Alguersuari.