LeSean McCoy, Chip Kelly reportedly bickered throughout the 2014 NFL season

Chip Kelly has often cited LeSean McCoy's contract as a big reason why he decided to trade the franchise's all-time leading rusher. Eagles Chairman and CEO Jeffrey Lurie once suggested McCoy wasn't the best fit for Kelly's scheme. But money and scheme probably weren't the only reasons Kelly decided to move on. Check out what Tyler Dunne had to say in a recent profile on McCoy. It's a great piece, so read the whole thing.

Yet multiple sources say their personalities were not compatible for the long haul – that the two bickered throughout last season.

According to one source, Kelly was unhappy with McCoy when he threw away his personalized post-practice shake and at DeSean Jackson another time when he wouldn’t wear his sleep monitor. And when Kelly had a problem with McCoy – be it a comment in the media or a touchdown celebration – another source indicated he’d often have somebody else close to McCoy tell him to knock it off rather than address the back directly.

Even though they’d pass each other in the hall daily.

Said a source, "It’s a dictatorship there."

McCoy's behavior since the trade suggests he didn't have a great relationship with his former coach. McCoy essentially accused Kelly of being racist in the offseason and has refused to back down from those comments. Leading up to the Eagles-Bills game this week, McCoy said he doesn't dislike Kelly, but he has no desire to shake his hand.

Kelly told reporters he understands McCoy's disappointment with how the trade happened. The Eagles coach apologized and took accountability for the lack of communication.

I understand where he’s coming from, and if he doesn’t want to shake my hand, I understand that. But I will always shake his hand. If he extends his hand to me, I would always shake his hand. I have great respect for him as a player. Everything we asked him to do here, he did. He was an outstanding football player for two years here. The only reason he wasn’t [brought back] is because the money was too high. He’s still a really good football player in this league. I don’t know if I can say anything else besides that, but I do have great respect for LeSean.

Ultimately, as Dunne writes, it doesn't seem like Kelly and McCoy were a good fit for each other. Kelly wants players who buy in and McCoy has his own way of doing things. It's not hard to think their differences, along with other reasons, is what led McCoy being traded away.