If I had to toss an opinion in the ring I would say he was at least comparable to Brown and keeping in mind that he is a rookie, that translates into he compares pretty favorably.
It didn't get a good feel for him in coverage since we rotated Coleman to Gonzales's side (THANK GOD!) for most of the game or had another CB covering Tony G. I think if Earl is starting next week we will get a better picture since they will probably let him isolate on the Raider TEs. The trend in these 1st few weeks is to plant a CB or ball-hawk FS on the upper tier TEs that are in the game now. This is probably due in part to the emphasis on the 5yrd No Touch rule...it basically puts the LBs in a much tougher spot trying to cover athletic TEs (ala Gonzales, Heap, Shockey, ect..). My guess is Earl will be man up on the Raiders Doug Jolley as opposed to playing middle zone or covering RBs out of the backfield.