Alternates are permitted to be on-site at the championship in the event of a last-minute withdrawal. Regardless of when the withdrawal happens, the USGA alternate procedure is utilized. However, last minute withdrawals may be filled by on-site alternates due to the timing of the withdrawal.
The on-site privileges for alternates to practice, play practice rounds, etc… varies by championship. Alternates must notify the USGA via [email protected] if they plan on being on-site for a championship.