DeSean Jackson and Jeremy Maclin have spent their careers playing under the same head coach, offensive coordinator, and position coach. They have started together for four seasons, but the offense they're learning now under coach Chip Kelly is considerably different from what they've done in the past.

Among the changes: how they receive the play and how they run their routes. Instead of going to the huddle to hear the play from the quarterback, they get directions signaled from the sideline. The routes they run are different, and so are the options they have as they go through a particular route.

"I think that's the freedom that we're capable to have out there," Jackson said. "Depending on the defense, if the defender's way back, if we can beat them on the go, then that's the point. But if not, we're able to still, within the route, have the option to stop if the cornerback is bailing for his life to not get beat deep. So it's really a win for the receiver. Going out there, it's like you have a double route."

This is flexibility that Jackson said he never had in the past, when he needed to run a designated route. The new approach also requires the receivers to learn each pass-catcher's position on the field, because they could be lined up in any one of them on a given play.

"It's definitely tough, honestly, because I've never had to learn everybody's position," Jackson said. "I only really had to know one position, which was the 'Z' wide receiver. Now it's like I'm learning the 'X,' the 'A,' the 'Y,' and really just knowing the concepts of the offense. Right now, it's at a very comfortable level where I'm able to go out there and see the signals and go out there and get my job done."

Maclin said the same routes that the receivers ran last year are still there but that there are "different ways to do it."

The Eagles need the change to benefit both receivers. They are expected to be blue-chip players. Jackson, 26, was a 2008 second-round pick and is a two-time Pro Bowler. Maclin, 25, was a 2009 first-round pick who had more catches in his first four seasons than any receiver in franchise history, but he has yet to have a 1,000-yard season.

Both have displayed flashes of excellence with occasions of inconsistency. Their futures in Philadelphia are both promising and uncertain. Maclin is a free agent at the end of this season, while Jackson has little guaranteed money on his five-year contract beyond this season.

Since Maclin joined Jackson in the starting lineup four years ago, the Eagles have not addressed the position early in the draft or in the free-agent market. Even after Kelly took over in January, the biggest move at wide receiver was exchanging a sixth-round pick for a seventh-round pick to acquire Arrelious Benn.

Besides Jason Avant, who is 30 years old and not known for his speed, the Eagles lack experience and production at the position. Benn and Riley Cooper are the next most experienced receivers, and Damaris Johnson was on the roster last season. The other competition comes from a cadre of unremarkable candidates: B.J Cunningham, Nick Miller, Ifeanyi Momah, Will Murphy, Greg Salas, and Russell Shepard.

In another development, Kelly used Jackson and Maclin on punt returns during Monday's practice, although it's more likely that Jackson will return to that role than Maclin. However they're used, they must excel as receivers. They're the starters, the best receivers on the team, and central to the changes in the Eagles offense.

"You've got to realize, we've been doing things differently for five years - or my five years, this is my sixth year," Jackson said. "This is the first year, switching up and adjusting to how [Kelly] wants things done. So far, it's been good."