Jameis Winston didn't always dream of becoming a superstar in the NFL ... instead, the Tampa Bay Bucs QB says he wanted to work on FEET for a living.

The Pro Bowl signal caller revealed his childhood inspiration in a Twitter Q&A ... saying a family podiatrist left such a big impact on his life, he wanted to follow in her FOOTsteps.

Winston says the doc helped out with his grandma's type 2 diabetes and his dad's "terrible feet," and he developed a strong relationship with her over the years.

Hey, if the whole pro athlete thing doesn't work out ...