Tom's fresh off his sixth Super Bowl ring ... but he's 41 years old -- and there's no clear successor to him on the roster if Father Time somehow abruptly wins their yearly battle.
Enter Carter ... an NFL Hall of Famer and overall plugged in guy who says TB12's eventual replacement ain't in this year's draft -- it might be in free agency ... in the form of Kaepernick.
"I know that the Krafts are very, very fond of Colin Kaepernick," Carter said on FS1's "First Things First" ... "I'm just saying outside the box, if someone will do it, it will be the people in New England."
Kraft has been close with Trump for years -- but he's also been critical of the President. In fact, Kraft told NFL owners and players Trump's language referring to NFL kneelers was "divisive" and "horrible."
Carter says the Pats aren't known for drafting very well ... and says, "I believe you should start looking at other situations besides the draft for how they're going to look to get Tom Brady's replacement."
Of course, Kap's been out of the league since the 2016 season ... claiming the NFL has blackballed him because of his anthem kneeling protests.
But ... people close to the QB say he can still play -- with even his ex-49ers coach, Chip Kelly, telling TMZ Sports, "He's ready to go."