DeSean who?

It may take several more games to declare the offense fine without Jackson - particularly when it faces more man-to-man defense - but if the first game was any indication of how the outside receivers will fare this season, the Eagles should be fine.

Jeremy Maclin and Riley Cooper combined for just eight catches for 126 yards and a touchdown in the opener, but they were constantly open - Maclin, in particular - against the Jaguars' Cover 3-heavy zones.

"We've always had confidence in our receivers here in terms of getting open," coach Chip Kelly said. "I think we faced a little bit more zone, so obviously guys are going to run a little bit cleaner through zones than they are going to run through man coverage."

The Eagles are likely to see more man-to-man defense against the Colts on Monday night. They'll probably see it more the rest of the year. That's how it was last season. Kelly has spoken repeatedly about the amount of man coverage the Eagles faced last season.

But with Jackson leading the way in Kelly's first season, the passing attack hardly missed a beat. There were times when maybe Jackson had difficulty getting off the line against pressing cornerbacks, but he was just as successful beating them downfield.

Could Maclin, after missing a year following knee surgery, and Cooper, who hadn't started until Maclin's injury last year, get open as often against man coverage?

"They said the same exact thing last year and we led the league in plus-20 plays," Cooper said. "People are always going to talk."

The Eagles have spent additional time on beating man-to-man coverage, according to receiver Jeff Maehl. They face it every practice against man-press corners Cary Williams and Bradley Fletcher.

Kelly has also stressed the importance of having bigger receivers to combat man-to-man defense. Cooper is 6-foot-4, 230 pounds. Rookie Jordan Matthews is 6-3, 212 pounds. Only the 6-foot, 198-pound Maclin wouldn't qualify as larger than most receivers.

"One of strongest points of my game through my career has been getting open no matter the coverage," Maclin said. "Zone or man-to-man."

He proved he could get open in Kelly's offense against the zone. He'll soon get plenty of opportunities to prove he can do it against man-to-man.

Casey bides time

Tight end James Casey played 154 of the team's 1,104 offensive snaps last season.

That's approximately $25,000 per snap based on the $4 million he was paid in the first season of a three-year contract he signed as a free agent.

Casey, of course, wanted to play more. He did as last season progressed, with 82 percent of his snaps coming in the second half. But Casey was back riding the pine for most of Sunday's opener against the Jaguars. He saw the field for only five plays.

"Absolutely, I want to be on the field. Everyone knows I want to be on the field," Casey said this week. "At the same time, there are only 11 guys that can get on the field. They know I'm pushing Brent [Celek] and Zach [Ertz] to get on the field. They know I want to play. They know I think I should play. But it's part of the business."

If Casey is to play more, it will likely come at Celek's expense. Last season, it was Ertz who mostly came off the field if Chip Kelly wanted two run-blocking tight ends. But it will be difficult for Kelly to keep the blossoming Ertz on the sideline. Celek, meanwhile, has done little to suggest that he is slowing down, particularly as a blocker.

The Eagles had envisioned using Casey as a TE-HB hybrid - as he was often used with the Texans. But when Ertz was on the board early in the second round of the 2013 draft, the Eagles didn't pass. Getting a potential Pro Bowl tight end vs. overpaying Casey is probably a choice the team would make every time.

Casey has never complained.

"I've been the very first guy in the building since I've been on this team," he said. "I get here at 5:10, 5:15 every single morning, and I'm not just sitting in the locker room [yakking]."

The 29-year-old Casey is still a valuable player on special teams. He said he's on every unit. But he wants to play more on offense and now he has rookie Trey Burton nipping at his heels. They have different skill sets, but Burton could replace Casey, whose third year is without any guaranteed money, next season.

"We're fortunate to have such good tight ends," Casey said. "But for me personally and for Trey, it's kind of harder for us to get on the field. We're pushing each other each day."

Five questions:

Cedric Thornton

A weekly Q&A with an Eagle:

Q: If you could choose to stay a certain age forever, what age would it be, and why?

A: Teenager. Because you've got no responsibilities, staying home with your mom, and those are the fun experience years.

Q: If you could have any super power, what would it be?

A: To be able to transform.

Q: If you were NFL commissioner, what would be the one thing you would change about the league?

A: I would pay us more.

Q: Who wins a fight between a bear and a shark in five feet of water and why?

A: The bear. Supposing the bear would be taller than five feet . . . he'll just treat it like he's fishing.

Q: If you could have lunch with one person from any time period, dead or alive, who would it be and why?

A: Reggie White. He played for the Eagles, he was a great player, and I would want to pick his brain and see his football side and his spiritual side.

Inside the game

Brandon Graham played a third of his snaps Sunday at the "Jack" outside linebacker spot in place of Connor Barwin. Last season, Graham played all his snaps at the "Predator" backing up Trent Cole because he would get to pass-rush the majority of time.

Graham still struggles in coverage and playing in space, but the Eagles feel that if he can play the Jack on base downs when opposing offenses typically run than they can utilize his downhill tendencies and give Barwin a few extra breathers.

"I finally gained their trust," Graham said.

Ideally, top pick Marcus Smith would back up Barwin, but he's still not ready. Mostly, it appears, the Eagles want to give Graham more opportunities to rush.

"One thing I know I can do for sure is go get that passer," Graham said.

Tight end Zach Ertz has been marked as a rising player because of his combination of speed, strength and ball catching. But his versatility as a multiple-spot receiver could ultimately make him the Eagles' most dangerous threat downfield.

"It's a product of him knowing and understanding a lot more about what we are doing and then also what getting him in the game elicits from the defensive responsibility," coach Chip Kelly said.

Ertz lined up at the front- and backside tight end spots, in the slot and split wide against the Jaguars. There's a potential mismatch wherever he lines up.

"I like to think I know the offense as well as the quarterback - know where everyone is supposed to be on each and every pass play," Ertz said.

Inside the locker room

Najee Goode was the first inside linebacker off the bench before he suffered a season-ending pectoral muscle injury. He could play for either DeMeco Ryans or Mychal Kendricks even though each has different responsibilities. The Eagles signed Emmanuel Acho off the practice squad to replace Goode and he has been practicing behind Ryans this week. Casey Matthews has been Kendricks' backup. Both will likely be active Monday, but if either Ryans or Kendricks was to go down, the next man up will likely depend on which starter leaves.

Receiver Josh Huff (shoulder) and offensive lineman Matt Tobin (ankle) didn't practice on Thursday and neither is expected to play against the Colts. Huff said that he was 85 percent. "Every day I'm making progress," Huff said. "Every day I'm getting stronger. My goal for when I come back is to just be in tip-top shape and just make sure my shoulder is strong enough so I can take hits." Tobin said he did some post-practice work for the first time since his injury. He intimated that he could be sidelined for longer than just the next game.

By the numbers

33 Percentage of pass plays in which Mychal Kendricks rushed the passer in the Jaguars game, according to Pro Football Focus. Last season, the Eagles linebacker rushed 20 percent of pass plays.

10 Percentage increase in plays for defensive end Vinny Curry, who played 36 percent of snaps on Sunday as opposed to 26 percent last season.

5.6 Average yards per play for the Eagles in the opener when they had two-tight end personnel (30 plays for 168 yards). The Eagles averaged 4.8 yards for the other 52 plays.

jmclane@phillynews.com

@Jeff_McLane