There is a great reason why Bush is sitting so much. It's because teams are putting eight guys in the box and shutting down the rushing lanes. They're rushing five or more of those guys which causes us to use our tightends and runningbacks as blockers. Most of the game we've only got two guys running routes. We can't spread teams out and properly use Bush because we need him to block. Since Thomas and Lane are bigger better blockers, we've been using them more to help protect Tannehill. If our front five were capable of doing a better job protecting Tannehill, then I think we'd see a lot more of Bush, and a lot more of the rest of our receivers.
Good assessment. The lack of a real threat in the receiving game is also a reason. Hartline. And Bess have both done well, but lets face it, they don't scare the defense or command a double team.
That too plays a factor. Teams know that they can cover Bess and Hartline with two corners and a safety high. All they need to do is jam them at the line and keep that safety over the top in case they get loose.
I know people will say that we need to run a screen pass to Bush. Well, since the other team will already have eight in the box, all they will need to do is assign one linebacker to shadow Bush. If they smell a screen, they simply break on the ball and blow up the play. That is why we've been ineffective at running screens this year. Teams are shadowing our runningbacks.
The only time I've seen our offense be truly effective is when we run four routes (ie. Bess, Hartline, Bush, and Fasano all run a route, Lane blocks). In that scenario we move the ball very well. But unfortunately the protection for Tannehill is poor when we do that. By spreading our opponents out, we leave Tannehill at risk because or line is insufficient right now.