It is believed that Renault tried to sign the contracted Toro Rosso driver for 2017, while Prost said that the 22-year-old was also good enough to drive for Ferrari.
"For me, that someone like Prost says that about me, you can imagine how that makes me feel. He is one of the most important people in Formula 1 - for me, he was on the same level as Ayrton Senna," he is quoted as saying by the Spanish press.
"Three or four years ago I would not have imagined someone saying something like that about me, so it means I have to keep doing things just as I have done."
However, Carlos Sainz's famous father has warned the youngster to focus on 2017 rather than consider a team switch for 2018.
Sainz Jr agrees: "I'll talk about 2018 when I'm finished 2017. Right now, without having done the first race, to think this is the year for me to make the leap is to take energy from one place and put it somewhere else.
"All my energy is on Melbourne, then China, then Bahrain. Race by race, and then we'll see where we will be."
The 2017 calendar commences this weekend in Melbourne.