The build-out line is a component of the USSF's Player Development Initiative. It designates special rules in the 10U game that relate to offside and goalkeeper distribution.

First adopted by AYSO in the 2017/18 season it continues to evolve in minor ways each year.

Here's is the latest incarnation of the rules surrounding the build-out Line. It also explains the rationale behind the decision to implement this initiative and how it relates to the modern game.