Against the Cleveland Cavaliers, the Celtics officially retired the jersey of Paul Pierce, who is now remembered as a Celtics legend. The future NBA Hall-of-Famer stuck it out with the Celtics since he was drafted in 1998.

Alongside of Kevin Garnett and Ray Allen, Pierce delivered a championship to the Celtics in 2008, breaking a 22-year long title drought. Usually, championship teams stick together years after their demise. Apparently, that hasn't been the case for the Celtics.

When Allen left the Celtics in 2013 to join the rival Miami Heat, many Celtic players were disgusted. Somehow, Allen coincidentally failed to show up to Pierce's jersey retirement ceremony on Sunday, which angered many fans. Former Celtics head coach Doc Rivers defended Allen and explained why Allen opted to skip the event, per The Boston Globe's Gary Washburn.

“Listen, I think that’s going to happen,” Rivers said of a potential Big Three reunion. “I did think it would have been great for Ray to have been there. But there’s just angst right now, and in Ray’s defense, I know he thought about coming. I can tell you that, because I talked to him personally. He didn’t know if he should. He didn’t know if it was the right time. He really didn’t want to take anything away from Paul or be a distraction, and he won’t be, and that’s what we’ve got to convince him of. If he would have been there, the fans would have cheered for him. That will happen eventually; you’ve just got to figure out when.”

The beef between Allen and the Celtics have obviously reached an all-time high after this incident. Hopefully, what Rivers has stated holds true and that the entire 2008 Celtics team can settle their differences soon.