Kendrick Perkins is explaining the background of a notorious NBA feud. Kyle Terada-USA TODAY Sports

There has been tension over the years among the 2008 Boston Celtics mostly centering around Ray Allen.

Allen left the Celtics to sign with the rival Miami Heat after the 2011-12 season, which upset many of his former teammates. Kevin Garnett said at the time that he lost Allen’s phone number. KG still has hard feelings toward Allen over it.

Rajon Rondo is the other former Celtic who has had beef with Allen. Rondo said Allen wasn’t invited to the team’s 10-year anniversary celebration of the 2008 championship. Rondo also took a shot at Allen over the shooting guard’s book.

So why does Rondo hate Allen, aside from Ray leaving for Miami? According to former Celtics center Kendrick Perkins, it’s because Rondo found out that Allen supported Boston trading Rondo for Chris Paul.

Perkins shared the story on SiriusXM NBA Radio.

Perkins explained: 

“It was brought to the table, ‘what if we trade Rondo and get CP?’ And KG and Paul (Pierce) were like, ‘no, we ain’t doing that. As great as CP is, we just won the championship. We’re rocking with [Rondo].’ Ray was like, ‘nah, let’s do it.’ And what happened was Rondo ended up finding out about it, and that was it from there.

“It was even to the point we brought boxing gloves to the gym and we made them box it out.”

Rondo and Allen remained teammates for a few more seasons even after that, but obviously tension continued, and Rondo still was holding a grudge toward Allen a decade later. This story from Perkins helps explain why.

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