What happened: The U.S. closes its September window against Chile with four changes to the starting XI. Julian Hall, Adri Mehmeti, Neil Pierre and Frankie Westfield step in for their first starts. Gio Reyna remains from the side that beat Peru 4-1 on Saturday.

Why it matters: Pochettino continues broad rotation after handing 11 senior debuts earlier in the window. The Chile date functions as an audition for depth roles behind the regular starters. Strong shifts from the new starters put pressure on October selection.

What to watch: The window closes against Chile on Tuesday night. Second-half substitutions will show how much trust the staff puts in the new starters.