Poll shows Trump in lead in Massachusetts, with Sanders and Clinton tied.
Clinton's lead is down from 25 points in January to 11 in a new NBC/WSJ poll.
The aide is downplaying a Wall Street Journal poll that puts Ted Cruz in the lead.
The Bloomberg poll shows Rubio and Bush in a tight race for third place.
Former Florida Gov. Jeb Bush comes in second place at 16 percent.
Rubio's support has jumped 7 points, putting him behind only Trump.
Sanders leads by huge margins with independents and young voters.
Support for both senators has risen in a new national poll.
Trump has 41 percent support with Cruz at 11.
The poll showed Clinton leading by 18 points last month.