The most recent information on this topic comes from Bruins insider Jimmy Murphy:
"From what I hear, the players' issues with Bruce fell on deaf ears with Sweeney so they took it to Neely," said the source as per Murphy. "I've heard Neely and Cassidy didn't always see eye to eye and maybe that's all he needed to justify firing him? Who knows? But that's what it sounds like."
Bruins Bergeron added on this subject also:
"Those rumors are completely unfounded and I won't waste any energy on that," said Bergeron last week. "It's really the speculation of idiots and a waste of time."
It seems like Bruce wasn't really appreciated by the Bruins players...