Without DeSean Jackson to stretch the field, Eagles coach Chip Kelly has to find other options and strategies at wide receiver.
On the face of it, the release of Jackson leaves the Eagles precariously thin at wide receiver. Maclin is recovering from a torn ACL that cost him the entire 2013 season, so it's hard to know for sure that he can be counted on. And I don't think it's insulting Cooper to suggest that he benefited from having Jackson on the field with him last year. The 2013 Eagles used Jackson in motion all over the formation, often as bait to force the defense into showing where the coverage was going. And Jackson's rare speed has always led defenses to commit at least some double coverage to him.
That said, Chip Kelly surely has a plan, or more likely many plans, for how to make up for the on-field loss of Jackson. It's easy to imagine Sproles being a part of it. He's not a wide receiver, but he's a running back the Saints used almost exclusively on passing downs and can play some of the roles Jackson played last year when he lined up in the backfield. Sproles can also be split out wide or used in the slot. He does not have Jackson's speed, because no one does, and he's not a candidate to stretch the field deep or draw double coverage. But when the Eagles run those package plays where they force the defense to commit coverage one way before Nick Foles throws the ball, Sproles can be a helpful piece close to the line of scrimmage and can make things happen when he catches the ball in space.
Maclin is a question mark. If healthy, he likely replaces Jackson to the extent that Jackson was used last year on the outside. Maclin used to have elite speed, so we'll see the extent to which the effects of the ACL surgery have changed that. But Kelly surely had specific plans for Maclin last year before Maclin got hurt, so there are elements to the offense involving him that we probably haven't even seen yet.
If Maclin isn't healthy, the Eagles have a major issue. They like Arrelious Benn, whom they acquired last offseason in a trade with Tampa Bay, but he himself is coming off ACL surgery. Damaris Johnson is seen as a potential playmaker in space, but we haven't seen it translate on the field very much yet. And it's worth noting that this year's draft is considered to be an excellent draft for the wide receiver position. The Eagles could find a receiver in the early rounds to add to their stable, and if that guy were to develop quickly, he could be a potential solution as well.
One thing of which I'm sure is that Kelly didn't release Jackson without first considering, in painstaking detail, myriad ways of attempting to replace his production on the field. Kelly does nothing without a plan and extensive preparation. He has created for himself a puzzle that will be more difficult to solve without Jackson than last year's was with him. But he does still have a decent number of good-looking tools at his disposal to help him solve it.