Rob Gronkowski is opening up about his decision to leave New England -- admitting they weren't exactly an easy organization to play for ... but he respects the guys in charge.
"I'm very thankful for the 9 years I had with the New England Patriots," Gronk said during a call with reporters on Wednesday ... "I had the best coach, hands down. [Bill Belichick and Robert Kraft] are two guys I look up to."
"I'm not going to sit here and say that's an easy organization to play for. What I've learned there, I'm definitely going to take it with me.