1) LeSean McCoy totaled more carries than any other running back in the NFL during the past two seasons. The Eagles might spread those carries out this year among multiple running backs, which was what Chip Kelly wanted after dealing McCoy. Even though DeMarco Murray led the NFL in rushing last season (and carried the ball more times than any other player since 2006), Kelly has said since the spring that he does not want the Eagles to rely on one running back as much as they did during the past two seasons. So expect Ryan Mathews to also have a big role in the offense.

"If you have multiple backs you don't lose anything when you take one out, and I think we probably relied on one too much in the last couple of years," Kelly said. "But I have great confidence in those other guys that when they go into the game you don't have to change what you're doing. Ryan and DeMarco are very similar in terms of how they run and what they're doing so it's almost like you think you catch your breath when you take DeMarco out of the game but then here comes Ryan, that's going to be a real difficult task for people, I think."

Kelly's argument that they have their current backfield for the price of McCoy does not totally add up, because Kelly focuses on the 2015 cap number (which could be adjusted, as it was for McCoy in Buffalo), and not the total compensation. So Kelly can cite Murray's $5 million cap number and Mathews' $2 million cap number, but that doesn't take into the account the combined $16 million guaranteed they have remaining on their deals. Kelly argued that the Eagles considered what the salary cap would be in those future seasons when they offered Murray a five-year, $40 million deal.

"The cap goes up in future years," Kelly said. "So look at the percentage of the cap. When the cap continues to go up, the value of this player's contract is less than the value of that player's contract. So you're not looking at apples and oranges. …When we look at the money guaranteed to DeMarco down the road, the cap goes up when we go down the road, so the percentage of the cap is less than the percentage of the cap that we're paying him."

Before the Eagles signed Mathews or Murray, it appeared they were going to sign Frank Gore. The veteran running back was set to join the Eagles during the open tampering period, but he changed his mind and signed with the Indianapolis Colts. Kelly said that was "very misrepresented."

"Nothing was a done deal,' he said. "We got a chance to talk to him finally at 4…whatever day it opened up. He said he was going to go to Indianapolis. After Indianapolis, that was his first visit, then he was going to make a second visit if it didn't work out at Indianapolis."

2) The Eagles' emphasis on sports science under Chip Kelly has become a popular topic since Kelly arrived in 2013. Kelly said sports science started to interest him when he took over as Oregon's coach in 2009 – it wasn't much of a consideration when he was an assistant coach at New Hampshire.

"I just think our schedule, in terms of when I took over at Oregon, talking to our strength and conditioning coach, when we were going to practice and how we were going to practice," Kelly said.

He was a first-time head coach who looked at coaching with an open mind. The attitude was triggered by a simple question: How do you affect the play on the field?

"And I think it's a huge way to affect the play of the field," Kelly said. "You always wanted to have a team that was in great shape but you also wanted to have a team that was fresh. So it was a combination of, how does that work? What's the best ways to go about it? So I think if you can invest in…the product is the player and you're trying to invest in the player."

Kelly said the program has been tweaked since he arrived, but there have not be any drastic changes. Former cornerback Cary Williams was critical of the way the Eagles practiced last season, but Kelly said it did not prompt him to make any changes.

"We listen to our players every day," Kelly said. "We get feedback from them on a daily basis so I think we all understand that. But if you ask Malcolm Jenkins, it's the best he's ever felt at the end of his year, the same thing for Connor [Barwin], the same thing for most of our players that you talk to. I also look at games lost to injured reserve. We were first a year ago, we were fifth last year. We have the best average of the last two years, so I think there is a lot of data that is positive in terms of what we're doing."

3) When asked what makes a "Chip Kelly player", Kelly said he did not understand the question. Further pressed, he explained he wants players who are passionate and hard-working, as explained in the Sunday Inquirer. But the best explanation of what he seeks might have come out of his mouth two springs ago, when he said he wants players who "love playing football, not what football gets them."

The challenge would seem to be how to discern that in a player, which Kelly admitted is easier to do during the draft process than in free agency.

"I think you've got to sit down and meet with them," Kelly said. "Obviously, in free agency,  you don't get that opportunity, but in the draft process, you do. I think in this year's class, we've got guys like Eric Rowe and Nelson and JaCorey [Shepherd] and those guys, that love playing football, but that's just through what the scouts do, in terms of the questions they get answered when they're on the road, at the beginning aspect of this, when we get exposure to them, whether it be at the Senior Bowl or the Combine, or when we visit their campus, or they come to visit us here --- just trying to figure out what that individual's all about."

zberman@phillynews.com

@ZBerm