Boston Celtics All-Star forward Jaylen Brown apparently has some frustration towards the only organization he's ever known, according to Tracy McGrady. "I think his frustration lies deeply within the organization and other things that we don't really have the details to," McGrady said on an episode of Cousins with Vince Carter & Tracy McGrady. "There's just been a lot of stuff that I've been hearing just going on with the Boston organization, with JB." For his part, Celtics president of operations Brad Stevens denied that Brown ever expressed any frustrations towards the organization. “I talked to Jaylen Monday a little bit after, just real quickly and it was nothing but positive. He has not expressed those frustrations to me,” Stevens said. “We’ve been here 10 years together, and I do think that — obviously I love JB and everybody around here loves JB.…