Brady's inner circle, according to nearly all knowledgeable sources, consists of his wife, his sister, his father, Don Yee, Alex Guerrero and less than a handful of friends he has known for years. One has to really struggle to get their total number to ten. They are part of that circle because they don't talk. So, no one who wants to remain part of that privileged group would talk about something this important to anyone outside that group, assuming that Brady has even talked to more than one or two of them about it. In fact, Brady has even tried to rein in his dad's public comments, so even his dad might not know what is really going on.
That means the "good Boston sports player," as the source is described, is reporting something he heard from within the Patriots organization or from someone very close to that organization. The only important conversations from within that organization that take place with Brady and Yee are conversations held by the Krafts and Belichick. When it's time to dot the i's and cross the t's, that group would expand to include Nick Caserio.
So, this is a rumor based on what someone close to the organization has heard about private conversations between Brady & Yee on one side and Belichick & the Krafts on the other side. A "Boston sports player" could either be an athlete or a professional who is part of the Boston sports establishment...I assume that description is vague for a reason.
I don't question the sincerity of the OP for posting it (the OP acknowledges that it is what it is: an unverifiable rumor) and I certainly hope it is true. But, it's pretty flimsy stuff.