It is common for teams to borrow eligible players from other teams within the club for games, and is a guiding principle of club soccer.
Requests to borrow players from another team should be addressed by email to the coach of the loaning team, with the Director of Coaching copied. The loaning coach may then delegate administrative responsibility to the Team Manager. The borrowing team should have a copy of the borrowed player's US Club Registration Form (which includes medical release) and the player pass ... at all times during the event in question. No Player Loan form is required when borrowing players within the same club.
Borrowing players helps strengthen the relationships among club teams and players. It is also a good starting point when considering requests for players to change teams, as it provides valuable experience to aid in the decision.