I saw that TML had a write-up of this in the lab, and since I can't get into the lab, I decided to lab it again, and see what I could find.
Here's what I found:
The Inside WR does a screen, so you can make an unexpected screen out if this play by using slide protection either left or right, throwing it fast and running in whatever direction you slide protected.
On the other side, you have a flat curl combo that gets open on a regular cover 3.
The HB runs a delayed route, so if its a blitz you can dump it off to him or the WR on the screen route for some good yardage.
The outside left WR should be hot routed to a smart routed out route, or a fade. it should be an RC route other than streak.
You don't have to use slide protection for the screen, bucz with or without it, this play is money.
Subject: Shotgun 4 WR- Slot outside 