Nah, Trump as the Republican candidate
He is already behind by double digits in swing states to both Sanders and Clinton. Carson is up vs both, but will decline similarly once he gets more of the spotlight. Carson of course has the advantage of demographics and of not being an obvious asshole.
I don't buy the national numbers since they are trying to ask people who may or may not vote next year about candidates who may or may not face one another. The state numbers are far more legitimate imo.