WR - false start vs. illegal motion vs. illegal shift

[bisonlj]

Originally Posted by stegenref

I had a game last night where a wide receiver (on the line) started moving before the snap and actually crossed the line of scrimmage before the ball was snapped. I blew my whistle, threw my flag, and signalled the white hat that I had a false start. We went ahead and enforced it, but at halftime we talked about it some more. He told me I called it correctly, but he said if the receiver had not crossed the LOS, it would've been a live ball foul for illegal motion / shift and that case I should throw the flag but not kill the play by blowing my whistle. The Umpire told me that only interior linemen can false start.

So what is the difference between a false start, illegal motion, and illegal shift for wideouts and / or those in the backfield?

Sounds like your white hat needs a lesson false start vs. illegal motion. If the receiver did anything that simulated action at the snap, he has committed a false start. The rule is very clear on that:

Rule 7-1-7a
After the ball is marked ready for play and before the snap begins, no false start shall be made by any A player. It is a false start if a shift or feigned charge simulates action at the snap.

What your white hat is probably confused about is the running back who rocks out of his set position a little early and it could have been considered the beginning of shift if not for the snap. There are differing opinions on whether that should be a false start or illegal motion.