Brown and Baskett both stepped right in as rookie wideouts, started games, and played extremely well.  LJ Smith came right in as a Tight End and helped out too.  Looking down the list at all positions, Mike Patterson started as a rookie, Omar Gaither, Todd Herremanns, Ryan Moats, LaJuan Ramsey, and Trent Cole all contributed.  Michael Lewis, Sheldon Brown, JR Reed, and Rod Hood all contributed in the backfield as rookies.

This "rookies don't contribute on the Eagles" thing seems to be a myth that has developed based on some freak occurances with marquee draft picks.

Shawn Andrews - was to be a rookie starter in 2004 but broke his leg in first game (imagine how good we would have been that year!)
Matt McCoy/Chris Gocong - both seemed to have issues picking up the defense, and Gocong was allegedly "injured".
Lito Sheppard - rested on his laurels of being drafted first and watched Sheldon Brown get to play first
Jeremy Bloom - injuries
Jason Avant - beaten out by Baskett
Brodrick Bunkley - holdout + out of shape
Kevin Kolb - not needed
Billy McMullen - just a dumb, dumb guy, beaten out by Greg Lewis
Winston Justice and Max Jean-Gilles - O-line depth workd out against them
Jerome McDougle - injuries in pre-season
Brian Westbrook - sitting behind Brian Mitchell and Duce Staley
Matt Ware - just wasn't very good

A lot of the non-contribution is injuries, just a handful is guys struggling in the system like McCoy or McMullen or taking the dumb road to the NFL like Bunkley and Sheppard.  And no one should have a problem with a rookie sitting and learning if the veteran ahead of them is an All-Pro (Kolb vs. McNabb, Westbrook vs. Mitchell, Justice vs. Thomas).  When the Eagles have had a healthy and mostly smart rookie class, we've seen significant constributions, such as 2005.  We all know how that campaign turned out.