This story seems bogus. It was published today. But Newsmax is basing its report on a February 7th article from RealClear.
Since then (2/7), Kerrey changed his mind and announced a couple of weeks ago.
according to an article from KearneyHub at 2PM today he was still in:
http://www.kearneyhub.com/news/opinion/article_bdd79870-6875-11e1-9005-001871e3ce6c.html