Serena Williams -- who owns a minority stake in the Miami Dolphins -- says she's convinced, if a team hired Colin Kaepernick, he would win the Super Bowl.

However, she's also convinced no one will ever hire Colin Kaepernick.

It's all part of her new interview with Time -- where Serena says she supports the rights of NFL players to protest during the national anthem.

When asked specifically about Colin -- whom she's only met twice -- Williams said she doubts an NFL team will hire him, especially after he filed his collusion grievance against the league.

But, as the Time article states, "She’s convinced Kaepernick would win a Super Bowl."

"He’d have so much to prove," Williams said ... "I would. I can’t imagine he would be any different. 'Man, I’m about to show out. Y’all gonna see stuff you’ve never seen before.'"

Interesting, since some think the Dolphins could use a QB right now ...

Williams also says she doesn't believe Kaepernick is a broken man because of the alleged blackballing -- she thinks it's the opposite because he's focusing on raising money for nonprofits.

"Colin is happy with what he’s doing ... Some people are different. He’s just different."