"It became clear at the end of the season that [Kelly] wanted to go at the wide-receiver position differently," Lurie said. "Chip and his staff were incredibly clear that for us to get better, we needed to take a step back and reconfigure the wide-receiver position.
"Like a lot of smart coaches, Chip knows exactly what he wants at every position. For Chip's offense, [Jackson] just was not a [good] fit. He was so clear that we had to get better there."
I know what you're thinking right now: How could a guy who caught 82 passes for 1,332 yards and nine touchdowns last season possibly not be a good fit?
How could a guy who finished second in the league in 20-plus- yard catches (25), ninth in yards per catch (16.2) and 13th in receptions for first downs (60) not be a good fit for any offense?
If you listened closely to Lurie, Kelly and Roseman, they listed 12.75 million reasons why.
That was what Jackson's salary-cap number would have been this season in the third year of the 5-year, $47 million contract he signed with the Eagles in March 2012.
It would have been the sixth highest salary-cap number among wide receivers in the league, behind only the Dolphins' Mike Wallace ($17.2 million), the Texans' Andre Johnson ($15.6 million), the Seahawks' Percy Harvin ($13.4 million), the Lions' Calvin Johnson and the Bucs' Vincent Jackson (both $13 million).
Of the 18 players who had more receptions than Jackson last season, only two - Andre and Calvin Johnson - had bigger 2014 cap numbers than DeSean. Of the 13 players who had more touchdown catches, only two - the Johnsons again - had a bigger cap number.
Jackson's cap number would have been higher than that of 20 of the league's 32 starting quarterbacks'. It would have been $3 million more than that of teammate LeSean McCoy, who led the league in rushing last season.
When the Eagles signed Jackson to that 5-year deal, both the team and the player essentially viewed it as a 2-year deal. Both sides knew it would either have to be restructured after the 2013 season or he would be released.
After putting up the best numbers of his career last season, Jackson wasn't in a restructuring kind of mood, unless it meant more money now.
After watching him fail to gain more than 60 receiving yards in five of his last six games last season, and after watching Saints cornerback Keenan Lewis manhandle Jackson in the playoffs, the Eagles weren't interested in giving him another pile of money.
Kelly said releasing Jackson was a football decision, but in the NFL, salary-cap economics go into just about every significant football decision. The Eagles coach admitted as much when he compared the Eagles' decision to cut Jackson to the Bucs releasing cornerback Darrelle Revis, the Bears releasing defensive end Julius Peppers and the Cowboys releasing DeMarcus Ware. Revis, Peppers and Ware have a combined total of 20 Pro Bowl appearances.
"It was just a decision that we made as a team that a lot of teams make at this point in time," Kelly said. "It's just part of the game of football."
No matter how fast and explosive Jackson is, no matter how many 20-plus-yard catches he had last year, the fact of the matter is that it's hard to justify having a 5-9 1/2, 175-pound receiver who got his lunch eaten in the playoffs taking up nearly $13 million of your cap space.
Wide receiver has become a big-man's position. It's about back-shoulder fades and being productive in the red zone. It's about being able to get off press coverage and fight big, physical cornerbacks for balls in the air.
The crop of wide receivers in next week's draft is considered the best in years. The thing you notice about them is that most of them are big. A lot bigger than Jackson. Seven of the draft's 10 top-rated wideouts are 6-foot or taller. Seven weigh at least 200 pounds and six weigh at least 210.
"It is a size league and you have to look at those things in certain situations," Kelly acknowledged yesterday.
Before they released Jackson, the Eagles tried to trade him. But Kelly said yesterday they didn't get a single offer. Not a one. That $12.75 million cap number was just too big of a negative.
"He had a very expensive contract," the Eagles coach said. "There's a guy who was one of the best corners in the NFL [Revis] was let go this year. That guy is a helluva player. But there's a lot of economics that get involved."
Said Lurie: "In today's NFL, it's not surprising that would happen [not being able to trade Jackson]. You don't see players with double-digit [salary-cap numbers] getting traded. You see them getting released."
The Eagles, who currently have about $21 million in cap space, had enough room to carry Jackson's high cap number this year. But it was clear that neither Kelly nor Roseman saw Jackson as a long-term Eagle. Better to get rid of him sooner than later, even if it meant getting nothing for him.
"We gave him the contract [2 years ago] because he's a really good player," Roseman said. "We felt comfortable with it. But 2 years is a long time. We had a lot of changes in 2 years, and circumstances change.
"We're trying to build something that lasts. With that comes hard decisions. When you're managing a team in the NFL, the amount of resources that you get in terms of salary cap and the players that come up in terms of contracts, you've got to make decisions. You've got to figure out how you're going to build your team and where you're going to put your resources.
"All of the decisions we made this offseason are about trying to put the best team together moving forward."
On Twitter: @Pdomo