Tight ends are moving pieces in Kelly's offense

For months, we've heard about how Chip Kelly was going to utilize his tight ends the way the Patriots did for the last three seasons.

And yet, when the Eagles hosted New England in the preseason opener on Friday and the first-team offense played, of the 21 plays in which Kelly called, only six required more than one tight end.

It was admittedly a small sample.

But that fact that James Casey did not garner a snap with the starters pointed to how difficult it will be for Kelly to get all three of his top tight ends 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 lined up his tight ends, 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.

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.

"I have the mentality where I want to block and that's the biggest thing," Ertz said. "It's going to be hard because I don't weigh as much as [defensive linemen], obviously. So it's a big technique thing."

On the Eagles' second play from scrimmage, the 6-foot-5, 250-pound Ertz lined up in the slot and was required to block Patriots linebacker Jerod Mayo once running back Chris Polk got the handoff. He whiffed.

Later, when the Eagles lined up in a "12" formation, in which two tight ends and two receivers were stacked wide, Ertz took a bad line on the defensive back and missed his initial block.

The tight ends are out there to block for the receivers in case the quarterback opts to throw a quick screen. Nick Foles handed off all three times the formation was used, but Ertz will have to improve on his technique since many believe Kelly will often employ the spread look.

On the three other occasions in which there was a two-tight end set, Ertz lined up in the slot and Celek was either in-line or in the backfield. Ertz has spent considerable time split wide in training camp, so it's fair to assume that he will be out there a fair amount once the season starts.

There were also several days when the Eagles practiced with a number of three-tight end sets with Celek, Ertz and Casey lining up in various formations. Kelly has said that he likes the mismatches tight ends can create, but it may be difficult to go heavy on tight ends on game days.

Even with the injuries at wide receiver, the Eagles still have four more than capable ones in DeSean Jackson, Jason Avant, Riley Cooper and Damaris Johnson. And they're loaded at running back with LeSean McCoy, Bryce Brown and Chris Polk.

If Kelly dresses three tight ends on game day, all 10 skill-position players will be battling to fill the maximum of five spots on any given play.

Clay Harbor, who tallied 354 snaps last season as the No. 2 tight end, has had a solid camp. He caught three passes for 47 yards on Friday. But the numbers don't look good and he started working out with the receivers on Sunday.

"I wasn't expecting it, but you've got to be ready for anything," Harbor said. "I feel the more things I can do, the more valuable it'll make you as a player."

Kelly likes tight ends. But four may be too many.

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