Pass eligibility with ineligible number

[gopher2]

Offense already has 5 linemen (50-79) in the game on the LOS in their traditional positions.  A 6th player, A6, (50-79) lines up as a split end and is the last man on the LOS.   On the snap A6 goes backwards 3 steps.   If the QB throws backwards to A6, and A6's position is behind the QB, then this is an allowable pass right?  My thinking is that none of the forward pass requirements have to be met.   Same concept as handing the ball off to your 300 pound DL playing fullback on the goal line, right?

[JustRules]

Any player can touch/catch a backward pass or take a handoff in the backfield if they are lined up as a back. Be careful trying either though. I've seen attempts to do both fail more than they work.