No surprise here. Even if Kyrie intended to re-sign with Boston, he still wasn't going to opt in to his final year. He'd sign a new max contract instead. Irving has been most linked to the Knicks and Nets with the ladder gaining momentum. The Celtics odds of re-signing their all-star point guard appear slim, though Danny Ainge hasn't given up yet.
Irving can't officially talk to other teams until the evening of June 30th, but we all know how that goes. Plenty of free agents tend to sign with new teams in the early AM on July 1st, so obviously some illegal communication takes place prior to then.
I'm expecting Kyrie to pick the Nets when it's all said and done.