Goal Line Pylon

[Forksref]

parepat -

NF 2-25-3 (lines)

"When related to a live ball in a runner's possession (touching inbounds) while the ball is over the out-of-bounds area, the goal line includes the extension beyond the sidelines."

Diving and leaving contact with the ground inbounds would not be compatible with the above citation. Thus, you would have to mark the ball OOB where the ball broke the sideline plane. The parantheses above indicates that the runner must be touching inbounds.