Which Defense Cards?

They have us drafting DL, LB, DB instead of drafting a team's entire defense. So what defensive card does HAL use when rolls show 4,5,6? Should we expect DL to map to run defense, LB to flats, DB to longer passes?

I've wondered that myself, and honestly I don't think anyone knows. I just draft, and hope for the best.
Much of this game is unclear. For example, I always make sure to take a linebacker corps that has at least one 6... even though I have no idea if the "emphasize" rule is even turned on. The football game is what it is. There are too many mystery settings and other elements that are beyond our control... Very frustrating to play.