While, in the eyes of the public, both former champions appeared to be friends following their UFC 137 bout last October.
With such an amicable relationship in the wake of battle, it perplexed many fans and analysts alike when Penn called out Diaz in his recent Twitter post.
Now, Penn's camp has come out to explain where the bad blood stems from and why Penn no longer respects Diaz.
In a post on BJPenn.com, Penn's Web site, social media manager Scott Hernandez explained that after their fight, Penn's relationship with Diaz had deteriorated and that they were no longer friends.
"The media may have painted a picture following the fight that things where (sic) cool," Hernandez said. "But they were not."
Hernandez points to their photo together in the locker room after the bout as an example of the public and the media receiving a false sense of the fighters' relationship.
"The one photo of the two together post-fight was taken by Cesar and B.J. and Nick did no socializing amongst each other after the fight," Hernandez said. "This was just a picture painted by the media, but it was never all flowers and butterflies."
Hernandez goes on to explain that Diaz's actions prior to and after the bout sparked Penn to lose respect for his former friend, listing four key moments that changed the former UFC champion's mind.
The break down began at the weigh-ins the day before they headlined UFC 137. After such a respectful tone was set in previous interviews and events, Penn was shocked when Diaz got in his face and attempted to strike him as they butted heads.
During the fight, Penn did not take kindly to a shoulder bump by the former Strikeforce champion in between rounds.
"The shoulder check was disrespectful, unwarranted and unnecessary," Hernandez said.
The third straw was when Diaz yelled at Jason Parillo, Penn's boxing coach, after the fight had ended and the two fighters were waiting for the decision to be read.
What finally put Penn over the edge was when Diaz apparently insulted him on HDNet, saying that he was "bitter" and had more to say on Penn and their fight.
"These actions are not of friends; these are actions of people who do not like each other," Hernandez said. "Nick crossed the line with B.J. on more than one occasion and that was all she wrote."
