Last night there were two plays which showed why Desean is a receiver, unlike Hester: one was Desean's TD, where he got behind the defense, kept concentration on a ball that he had little vision of due to Urlacher's hands, caught it in stride and tapped his feet down one extra time for good measure. Hester had a play where he was wide open for what should have been a TD, the ball hit him in stride in both hands and he dropped it.
There was one more play where Desean really impressed me; it was a slant pattern that only went for 11 yards, but watching the tape, he set up the defender and then made a lightning-quick move to the inside that left the route wide open. He really runs amazing routes.
Desean is a real receiver and he should be successful in the NFL, despite his small size. But he's also a rookie and he's made some rookie mistakes. Last night the muffed punt looked pretty bad, and McNabb also thought Desean should have turned his route up instead of out on the interception. (Although it looked to me like Desean made the right read; if McNabb had thrown it deep outside Desean was wide open, and there was a safety in the middle of the field). Dropping the ball before he got into the end zone a couple weeks ago was also boneheaded. Those kinds of things might keep him out of the starting lineup once the nominal starters are back.
If Desean stays in the starting lineup, I think you can expect production similar to what we've been seeing. If he gets bumped from the starting lineup, they'll still try to get some plays for him, and he'll probably do better than the Philly WR3 has done in recent memory, but I don't think he'll be startable in fantasy leagues.