Doc Rivers –- I Think I Know Why KG Hates Ray Allen ...

Doc Rivers is finally weighing in on the REAL beef between Kevin Garnett and Ray Allen -- and it's clear, he doesn't think the situation is as serious as some people are making it out to be.

Rivers -- who coached Kevin and Ray to a championship in Boston -- was leaving dinner last night with his son Austin Rivers (he plays for the Pelicans, they're in town to play the Lakers) ... when we talked about the heated rift between the NBA superstars.

The whole thing recently blew up after Allen gave an interview saying Kevin and Paul Pierce have refused to speak with him ever since he left Boston for the Miami Heat a few years ago. In fact, they won't even shake Ray's hand before a game.