Take a look at RCP averages: http://www.realclearpolitics.com/epolls/2016/president/us/2016_republican_presidential_nomination-3823.html
Trump is +10.4 average over seven current polls.
I think these polls are referring to his steady erosion nationally, losing badly to Clinton in the general, rather than relative to his primary opponents.
Oh, but we should pay attention to some HuffPoo concern troll junk instead of RCP! /SARC
Also, the article is clearly wrong about RCP per your link. Thanks for posting it! /NO SARC
Trump is +10.4 average over seven current polls.
People need to understand that polling just those voting in the republican primaries, and all of those voting in the general election are two, completely separate sample groups.
Yes, Virginia, it is possible for Trump to lead in the republican polls and trail in the general polls.
Those are Republican primary polls, the topic of the story is general election polls.