It's been clear from watching Chip Kelly's offense operate this summer that the 6-4, 255-pound Brent Celek still is going to be a big part of the Eagles' passing game.

Despite playing 82 percent of the team's offensive snaps, Celek was targeted just 83 times last year. That was just five fewer than wide receiver DeSean Jackson, who only played in 11 games. That will change this year. In Chip Kelly's offense, the tight ends seldom are asked to stay in and block on pass plays.

Celek was written off after the James Casey signing and the Zach Ertz draft pick, but it appears he has held onto the starting job. He'll enter the TE2 discussion.

Eagles TE James Casey did not garner a snap with the starters last Friday night against the Patriots, pointed to how difficult it will be for HC Chip Kelly to get all three of his top tight ends (Brent Celek, Zach Ertz) on the field, even with the expected bump in plays per game because of the up-tempo offense.

Of more interest was how the Eagles coach Chip Kelly lined up his tight ends against the Patriots last week, specifically Brent Celek, who played all 21 snaps.

Celek was all over the place and from four of five formations either blocked or ran pass routes. He started eight plays lined up as a halfback - at one end of the offensive line or another, a step back. Four times he started from the traditional tight end spot to the left or right of the tackle. He also lined up four times in the slot, three times split wide, and twice he started in the backfield to the left of the quarterback in the shotgun.

"In this offense, you've got to know every position, and they can just interchange you anywhere," Celek said Monday. "And it's fun. It's a new experience. You get to do different things. Guys like it."

Celek stayed in to block on 11 plays. Last season, Celek blocked around the same percentage of plays (470 of 888 snaps). As much as rookie Zach Ertz will be a part of the offense, his development as a blocker will probably keep Celek as the No. 1 tight end.

There had been some talk in Philly that Celek may actually be the odd man out with Zach Ertz, James Casey and Clay Harbor, who has been getting work with the WRs. But Ertz has struggled from the blocking aspect, something that Celek is pretty good at, and Casey didn't get any work with the first team against the Pats, so that seems unlikely right now. When healthy, the Eagles will have a capable offensive line that should limit Celek having to pass block, something he's been called on to do a lot over the last several years. Until we see more, no Eagle TE is more than a low-end TE2 option to draft right now and probably won't even get drafted in typical leagues. But Celek and Ertz certainly have some potential in this offense.

As much as Eagles rookie TE Zach Ertz will be a part of the offense, his development as a blocker will probably keep Brent Celek as the No. 1 tight end.

Ertz, who often split wide at Stanford, was not asked to run-block much in college. But he will be required to do so in Kelly's system. Celek blocked out of every formation. Ertz did as well and struggled against the Patriots.

Ertz's blocking could limit his playing time for a while until it improves, but his future looks pretty bright. That will likely limit his fantasy production, despite the fact he could gets some targets. Right now, it appears Celek is the clear TE1 on the Birds. Ironically, James Casey received no snaps with the first team.

Eagles TE Zach Ertz has been as good as advertised. The guess here is that he’ll end the season with more catches and receiving yards than Brent Celek or James Casey. Ertz has had some drops, but he’s also made some great catches. He’s lined up out wide a lot in the last two weeks.

Celek has been steady, but Ertz figures to take away a chunk of his targets.

Ertz is a TE2-type to monitor this August, though rookie tight ends are rarely fantasy relevant.

Even with WR Riley Cooper, the Eagles lack a reliable No. 2 wide receiver to complement DeSean Jackson and Jason Avant in the slot.

Their transition to a tight end-oriented system will be even more pronounced, and look for James Casey and Zach Ertz to play major roles with Brent Celek.

The Eagles don't plan to go outside the organization to replace Jeremy Maclin, which was a huge loss. With Cooper now in trouble for a racial slur, it makes sense the Birds look for more production from what is a deep group of tight ends. Celek probably has the most value of the three but it appears he could lose some work to the versatile Casey and rookie Ertz, who has even lined up on the outside at times in camp.

The Eagles have only had two full-squad training camp workouts so far. But ... TE Zach Ertz has gotten some attention for the way he’s played.

Ertz will likely stay behind Brent Celek and even utility guy James Casey, but all three have a chance to earn more playing time with the loss of WR Jeremy Maclin and the team unlikely to go outside the organization to replace him. Still, of the three, Celek is most likely to have the best fantasy value at this point.

Eagles wide receiver Jeremy Maclin suffered a torn ACL during practice Saturday at the NovaCare Complex and is expected to miss the 2013 season, a league source said.

Maclin was carted off the field Saturday about an hour into practice.

Maclin, a fourth-year wideout in the last year of his rookie deal, went down at the end of 7-on-7 drills.

Jason Avant will likely remain a slot receiver so expect names like Riley Cooper, Damaris Johnson, Arrelious Benn, B.J. Cunningham, Greg Salas along with rookies Ifeanyi Momah, Russell Shepard and Will Murphy to compete for the job. Benn and Cunningham were already out of practice after suffering minor injuries in Friday’s practice that rendered each one day to day. The Eagles could also use more multiple TE formations with Brent Celek, James Casey and rookie Zach Ertz.

Eagles Brent Celek is considered a blocking tight end, but Zach Ertz and James Casey are considered primarily receivers. HC Chip Kelly can split them wide, put them in the slot, put them in the backfield, or line them up tight to the line.

If Kelly considers Celek a blocking TE, it's not going to do much for his value on draft day. Avoid the Eagles' TEs when filling out your bench.

CNS Philly reporter Geoff Mosher said for the Eagles at tight end, it looks like a stretch for Clay Harbor to come back for year four. With Brent Celek, James Casey and Zach Ertz on the roster, it’s hard to imagine the Eagles paying Harbor’s $630,000 base salary if there’s no guarantee that he’ll be active on game day.