Did Cole Bease have a down year cause of his play or due to his limits and defenses adjusting to the routes he runs?
Beasley tore it up in 2016 on the short in and out routes taking advantage of underneath one-on-ones out of the slot. He was virtually uncoverable because the defender didn't know if he was going to break in or out since he did it so well.
Teams decided in 2017 that he was our top receiving threat and consistently bracketed him with inside and outside coverage. This allowed the bracket men to not bite when he faked the other way. Because the other receivers couldn't beat their coverage consistently, teams never were given a reason to drop the bracket.
Dallas, for the most part, did not try to use Beasley any differently, continuing to run him primarily on the short ins and outs. That may be because Beasley is a small, quick player, but not a particularly fast one. Press coverage can keep players like that from getting off the line with the DB having enough speed to make up ground when he does escape.
The Cowboys had him playing more at outside receiver during OTAs, so maybe they believe he can run routes against press coverage effectively. If he can, then it's an indictment against the staff that the coaches did not adjust to what defenses were doing and allow Beasley to take his routes further downfield.