On or Off?

SUPER BOWL
By John Turney

Offenses must have seven players on the line of scrimmage at the snap, otherwise, it is a penalty.

From the NFL rulebook:

Position of Players at Snap

1. Offensive team must have at least seven players on line.
2. Offensive players, not on line, must be at least one yard back at snap.
   (Exception: player who takes snap.)

However, in Super Bowl LII, on the play when Nick Foles caught a touchdown pass the Eagles appeared to have just six players on the line of scrimmage.

Credit: NBC, NFL Replay

The question is this:  Is the player at the top of this screenshot on or off the line? He is a yard off the line but if that is the rule, then it leaves only six Eagles on the line. 

However, why wasn't it called? Did the all-star team of referees miss it? Did they see it and thing the player at the top was actually ON the line of scrimmage?

I am sure post-game this question will come up and we will learn some answers.