It's not just about knowing what route to run. There are other nuances WRs have to know. That's why WRs usually don't make a huge impact their rookie year. It's easy enough to know you have to run a hook route or a slant on a given play. It's a totally different thing to know that if the corner is playing press you cut your route to the outside while if the defense is playing off you cut it inside. Or if they're showing blitz from your side you cut your route off early to give the QB an outlet to get rid of the ball. I think that was a big problem with the WRs this past Sunday, particularly with Marqise Lee. I read somewhere today, on twitter IIRC, that said Marqise didn't know what route to run on a lot of plays because he hadn't seen the coverage the Redskins were running on tape. As the season progresses there will obviously be more tape on defenses and the multiple coverages they like to run, but being early in the season with a new coaching staff, I have no doubt the Redskins had a lot of looks that the young receivers weren't ready for.

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