Lafell, Byrd, Ware(kind of), Hilliard, Tolliver, Scott, Williams, every offensive lineman in the past 4 years besides maybe 2, Beckham, Peterson, and every QB got worse or have gotten worse so far in their careers under Miles.
Their stats dropped because of the switch in QB from Matt Flynn to Jarrett Lee and then to Jefferson. Bad QB's hindered their stats. Look at Larry Fitzgerald's stats with John Skelton as his QB. He didn't just forget how to be a good WR. His QB sucks therefore his stats suck. Bad QB play affects the stats of every player on offense.
Also, Scott broke his clavicle during his senior year and Williams broke his ankle. Ciron Black had a deteriorated knee. Ware got passed up by Jeremy Hill who is a monster and OBJ's only problem is focus. OBJ's got skills but he's trying too hard to make things happen.