saad is right. Norbert just mentioned this a few weeks ago that WRs always run wide.
http://www.whatifsports.com/forums/Posts.aspx?ForumID=41&TopicID=449265&ThreadID=9718028#l_9718028
And to grindi's point above about not much difference between different kinds of FBs....Norbert also said that he does not think the engine is properly accounting for a better/worse blocking FB. He'll probably address that in the next update.