EAST RUTHERFORD, NJ - OCTOBER 06: DeSean Jackson #10 of the Philadelphia Eagles scores a touchdown in the fourth quarter as Prince Amukamara #20 of the New York Giants defends at MetLife Stadium on October 6, 2013 in East Rutherford, New Jersey.The Philadelphia Eagles defeated the New York Giants 36-21. (Photo by Elsa/Getty Images)

By Joseph Santoliquito

Philadelphia, PA (CBS) — In the days following DeSean Jackson’s release by the Eagles, speculation ran rampant as to the reasons why. Everything was to blame from Jackson’s petulant, rambunctious sideline behavior, to his alleged gang ties, to Jackson’s character, to this being Chip Kelly’s fault.

But what a number of sources close to and around the team, including current and former players as well as additional sources within the Eagles, revealed that Jackson was not very well liked by his teammates, was blatantly insubordinate, with temper tantrums that included supposedly screaming at Kelly in front of players, pushed the NFL rookie coach the way “a child would test boundaries,” and was more concerned with his rap label than he was about winning football games.

It also seemed as if Jackson never really embraced Kelly’s sports science system. Whereas everyone else appeared to buy into what Kelly was preaching, Jackson at times wasn’t in lockstep with the group. No “grown man” was going to tell Jackson what to eat and when to sleep. The two always seemed to be at odds with each other.

Their differences were as subtle as what socks to wear to pactice. Kelly is about uniformity. One of Kelly’s dress codes mandates white socks. Jackson wore black.

And their differences were as loud as music. Kelly likes music played at a certain decibel level throughout the locker room, and apparently, so do the players. When Jackson would blare his music, teammates would tell him to turn the volume down to a comfortable level. Jackson, a smirk on his face, would turn it up.

Teammates never questioned Jackson’s heart and passion for the game, according to some. They questioned his maturity.

It didn’t help, either, that Jackson clashed with wide receivers coach Bob Bicknell. Kelly has a deep almost brotherly relationship with Bicknell, whose father, Jack, was the long-time legendary Boston College coach. Kelly is an extended branch of the Jack Bicknell New England coaching tree.

So when Jackson was allegedly falling asleep and arriving late to position meetings, this rankled Bicknell and supposedly irritated Kelly. When Jackson blew up at Bicknell in Minnesota last December on the sideline, it pushed Kelly’s tolerance boundary to the brink.

Several other sources also suggested that Jeremy Maclin may have had an issue if Jackson returned to the Eagles in 2014. He wasn’t alone, if that’s true.

“The fact is, [Jackson] was a ‘me-guy’ with an attitude problem and [Maclin] is the complete opposite, a team guy, a great character guy you go to war with,” said one source. “Funny how [Jackson] has this anti-bully thing and he thought he could push [Kelly] around; he found out otherwise. His being cut had nothing to do with the gang stuff. The team knew it. Everyone knew he had ‘ties.’ Those were his guys. That’s okay. What put him out was his selfishness. He can try and spin it all he wants how he’s ‘a team player.’ He’s not. I’ll put it this way, when it came out last Friday that [Jackson] was released, more than a few guys were happy it happened. They said ‘good riddance.’ He had no real connection with anyone.

“Yes, you can say he was the type that could catch three TDs in a loss—everyone would be down, but you had the impression he was happy, because he got his. It was all about him. A lot of guys thought that way about him. [Kelly] came in here with a plan to get this thing right, and the one major [obstacle] standing in his way was [Jackson]. If we were going to move forward as a team, he had to go. Think about it—did anyone come right out and back him publicly? Not one.”

Why didn’t Andy Reid or Marty Mornhinweg, the Jets’ offensive coordinator, want any part of Jackson before he signed a three-year, $24-million contract with the Redskins on Wednesday?

They apparently knew the potential headache Jackson was.

Kelly received some culpability in the opinion of some. But numerous sources confirmed that “Big Balls” Chip should have been canonized St. Chip after putting up with the constantly complaining Jackson in 2013.

“You see little kids and how they cry and whine when they don’t get their way, that was D-Jax,” another source said. “I don’t think [Jackson] gave [Kelly] the respect he deserved. Kelly tried to reach [Jackson] plenty of times and [Jackson] tuned him out. Then you look at team functions, when everyone is out together at charity things or social stuff. He was the one missing. It was like he was in ‘D-Jax world’ and we just happened to be there.

“With Reid, [Jackson] tried pushing boundaries there, too, but he looked at Reid, I think, much differently than he looked at [Kelly]. Reid came in with an NFL pedigree. He was the guy that drafted [Jackson]. He was the one that called him on draft day and laid the law down right then: [Reid] wouldn’t tolerate any outside interference from anyone. Now you get this college guy [Kelly] and he’s not going to tell [Jackson] what to do. [Kelly] has a vision for this team—and he is a very old-school coach in a lot of ways. But there’s only so much [a coach] can take.”

In 2012, under Reid, Eagles’ management did reward Jackson a new five-year deal worth $48 million. He did have some minor flare ups with the law. In 2009, Jackson was pulled over by police for having illegally tinted windows and it was discovered he had marijuana in the car.

Still, Jackson stayed.

“That was all [Reid’s] doing,” opined someone close to the situation that asked that his name not be used. “[Reid] thought he could control [Jackson]. He could, to a degree. Kelly put up with [Jackson] behind closed doors. A lot of guys didn’t like how he talked to [Kelly]. And a lot of guys just didn’t like him. They thought he was too into his rap label than he was about winning games. The guy performed, there’s no questioning that. But you had to keep a constant eye on him. Guys put in extra time. He didn’t. It’s like he never grew up.”

When Reid went, and with the death of his father, Bill, who succumbed to pancreatic cancer on May 14, 2009, Jackson in a sense lost two father figures. Then he was asked to deal with something completely different in Kelly, who in rebuilding a 4-12 team had no time to coddle. By then, an argument could be made, Jackson was a wandering soul without any anchors. When Michael Vick and Jason Avant, two Jackson nursemaids, left the Eagles, it appeared a foregone conclusion that Jackson would be gone, too.

Kelly doesn’t deal with conjecture or drama. He’s direct. He’s passionate. And intolerant of nonsense. Call him a genial Bill Belichick.

Asked why the Eagles have been reluctant to go public with how difficult Jackson was, sources said Kelly likes to keep in-house dirt in-house.

“That’s [Kelly’s] way,” said one source. “It pisses me off that [Kelly] comes off looking like the bad guy here. It wasn’t just [Kelly] that wanted him gone. [Kelly] got a lot of feedback from guys that felt we were better off without [Jackson], too. [Kelly] is very much a player’s coach. His office is open to anyone. Now [Jackson] is the Redskins’ problem. We have something good going here and it’s going to get better without [Jackson]. He had to go.”

Joseph Santoliquito is a contributing sports blogger for CBS Philly.