Throwin situation

[Scratch85]

Originally Posted by Snaqwells

7-6-4
If it's a pass from one OOB teammate to another during an endline throwin, B1 may not reach across. That is a delay of game incident.

I can't find a rule against this either. I find rules involving a "thrower", but the player that is passing it along his endline is not a "thrower" by definition 4-42-1. The above action doesn't keep the ball from becoming live, that happened when it was at the disposal of the thrower, even though the thrower doesn't have posession of it yet.

I'm sure this will click with me soon. Please bear with me and help me get it. What is the rule that makes the above situation a delay of game?