A betting man may be inclined to wager on the tight ends, specifically Zach Ertz, when trying to decipher who will benefit from the departures of wide receivers DeSean Jackson and Avant, who played 89 percent and 71 percent of the offense's plays, respectively, in 2013.
"I'm so confident this year in my abilities," Ertz said this week. "Last year, I was a wide-eyed rookie. I wasn't even here for OTAs. It's a completely different situation. I have confidence in myself, and I think the coaches do, as well."
Kelly and his offensive assistants had confidence in Ertz in 2013, increasing his playing time in the second half of the season. But there were times down the stretch when Ertz came off the field for James Casey in two-tight-end sets.
Why? Because his blocking, particularly in the running game, was not consistent enough. Ertz said that his increased strength and better attitude have made him a better blocker. His coaches and teammates agree.
"Last year, he didn't really believe he could block anybody in the NFL," Eagles linebacker Connor Barwin said. "And I think this year, he's got some new muscles and at least he's really trying to block people."
The more effectively Ertz blocks, the more he'll play, especially on first down. The Eagles went with two-tight-end sets 26 percent of the time on first and 10 last year, placing them somewhere in the middle of the NFL. But they averaged a league-best 8.1 yards per play.
Around the middle of the season, Kelly and company started using more two-tight-end sets. Eagles tight ends - starter Brent Celek, Ertz, and Casey - played 24 percent of offensive downs in the first half of the season, 29 percent in the second.
The second-half increase may seem marginal, but the tight end group was more productive catching passes - 30 receptions for 504 yards and two touchdowns in the first half; 41 catches for 564 yards and eight touchdowns in the second. The running game also kept humming. And, well, the Eagles did go 7-1.
There were many reasons for that strong finish. And countering defenses played a large part in using more two-tight-end sets. That will often dictate personnel. But Kelly also will play to his strengths, and there's something appealing about having three tight ends who can catch and block.
"It's tough for defenses," Celek said. "When you have guys that are versatile and can do anything, what do they do? Do they put a nickel in the game? Do they put an extra linebacker in? What is it?"
If the opposing defense has a safety on the tight end in the slot, chances are the Eagles are going to run. If there's a linebacker on the tight end, the odds favor a pass. Last year, the Eagles' run-pass ratio on first and 10 with two tight ends was 61-39.
Not many linebackers could run with Ertz by the end of last season. There may not be any this season.
"I'm just more explosive," Ertz said. "I worked hard in the offseason."
Offensive coordinator Pat Shurmur said that Ertz "made the biggest improvement" among the tight ends "because he's the youngest guy." But he said the entire unit has improved. "I think we can use any combination of one, two, or three of them at any time."
More tight ends mean less at another position. When the Eagles went with one tight end last season, it was often the superior-blocking Celek. The expected progression of Ertz suggests he could cut into Celek's playing time.
"The first couple of games it's probably going to be a lot of trial and error, see who gets open the most. Nick's going to find a groove with somebody, and they'll be the primary receiver," said Ertz, referring to quarterback Nick Foles. "We don't really know who it is right now. We have a lot of playmakers, a lot of mouths to feed."
It's a good problem to have.