The Midline out of shotgun is a play we ran several years ago when we had Freddie Barnes at qb. It is a great play to run against an even front defense if you have a fast physical qb who is not afraid to tangle with the big boys in the middle.
The QB and the F run together towards the lie of scrimmage with the QB decided to give or pull the ball based upon the front side DT. If the frontside DT decides to the A gap then the QB will pull and run through the B gap. If the DT goes to the B gap then the QB will give to the F who will take the ball up the A gap.
The blocking for the oline is as follows from left to right using the graph above.
LT expand the 5 technique
LG climb to fside lber. Important to coach you OL to run underneath the DT to get to the Lber. It will look exactly like the trap play you run.
C and RG Combo block into the Bside lber.
RT expand the 5 tech and do not let him cross face.
We have not run this play in several years however, I am looking for it to make a comeback in my playbook in the near future.