Kyrie Irving only just arrived in Boston, but there are already rumors that he could be on the move again next Summer. Irving, 26, has an opt-out clause in his contract that can make him an unrestricted free agent after the 2018-19 season and there's a belief that the Celtics are "scared" he's going to do just that.

Yahoo Sports' Chris Mannix explained on his podcast why the Celtics should be concerned about Irving leaving to join the New York Knicks as a free agent next summer.

"I think they're scared. I think they're scared and should be scared to some degree of Kyrie Irving walking in 2019. I know he had a great year, but you know there are people in Cleveland that will tell you that the Knicks should be considered a real threat for Kyrie Irving. Because Kyrie had talked about it—about playing with the Knicks with some players in that Cleveland locker room—from what I was told."

"You know, things can change. Obviously, you go to Boston and you become the face of the franchise. You're on a winning team. Maybe the mindset has changed significantly?"

In his first season with the Celtics, Irving averaged 24.4 points, 5.1 assists and 3.8 rebounds per game and was named an All-Star for the fifth time in his career. A knee surgery cause him to miss Boston's post-season run but the young team still managed to take the Cleveland Cavaliers to seven games in the Eastern Conference Finals. Not to mention, they played without All-Star forward Gordon Hayward for the entire season.

The Celtics are primed to be a contender for years to come, whereas the Knicks, coming off a 29-53 season, are once again in "rebuild mode" as they haven't reached the playoffs since the 2012-13 campaign.