Murdoch said Christie blew himself up while damaging Rubio.
Chip Englander will serve as a senior political adviser to Rubio.
Six superdelegates have pledged support to Clinton in New Hampshire.
He finished ahead of Jeb Bush by less than 1 point.
Ta-Nehisi Coates said he was "pleasantly stunned" by his New Hampshire finish.
Christie is reportedly meeting with top aides and a decision could come today.
The Florida senator is up 10 points in less than a month.
We need a strong leader with experience, ideas and resolve," the former president says.
The New York Daily News and the Union Leader have attacked Trump regularly.
"He’s not as conservative as me, and his record is not nearly as good as mine.”