The Boston Celtics' jersey retirement ceremony game for Paul Pierce was a star-studded event, as expected. However, there was one notable face missing.

On a day where Pierce had his jersey join the rafter of Celtics greats, former teammate Ray Allen was celebrating comedian George Lopez's most impressive athletic feat, per Bleacher Report:

Given that Paul Pierce enjoyed a long tenure with the Celtics, he had a number of his former teammates in attendance to witness the momentous occasion. Of course, the event featured the likes of Kevin Garnett, Rajon Rondo, and even Antoine Walker.However, it seems Allen's invitation must have gotten lost in the mail. Either that or things are still not all kosher between the one-time championship group.

Of course, it all started once Boston's tenure atop the Eastern Conference seemingly started to come to an end with the emergence of the Miami Heat's newly-formed Big 3. It was also during that time that Ray Allen felt his role on the Celtics was starting to diminish. As a result, he joined the Heat prior to the 2012 NBA season.

Needless to say, the move effectively cut off all ties between Allen and his former teammates in Pierce Garnett, and Rondo. Furthermore, it was not long before their dynasty was quickly replaced by the Heat. It was then accompanied by a massive rift between both sides up until Pierce and Allen reportedly squashed their beef prior to the 2017-18 NBA season. However, it is apparent that there stay may be some tension between the two following Sunday's events.