I think what he means is that if no candidate gets a majority of votes in a particular state during the general election, instead of awarding the EC votes to whoever got the plurality, then a runoff would be held between the two top vote getters for the EC votes.
That may, or may not, be good idea in theory, but the election cycle has already begun. A state which sought to change the rules in the middle of the election cycle would be handing the election to the Democrat candidate on a silver platter.