The rules about changing rosters for the 2021 Open, Mixed, and Senior USBCs are complicated by the fact that roster changes can take place either before the online stage of each event or after a team has qualified for the KO stage, but before play in the KO stage has started. To clarify, the USBF Board has decided that:

Roster Changes before the Event Starts

Until 2 days before play has commenced in any USBC, which may be before the online stage or the face to face stage, depending on the number of teams entered, teams may change their rosters with no restrictions, except that they must notify the USBF Secretary, any new pair on a team must submit a System Summary Form and ACBL Convention card within 4 days of being added, and a new pair may not employ any unusual bidding methods that no other pair in the event is using.

Roster Changes By teams After Online Stage - NOTE: this applies when a player on a Women's, Mixed or Senior team qualifies for the Bermuda Bowl as well as when players drop off teams between the online and face to face stages of play:

After completion of the online stage, if there is one, in any event, teams may change their roster subject to the following:

1. At least 4 players who met the play requirements for the qualifying stage(s) must remain on the team for the face to face stages. For the Mixed USBC, there must be 2 players of each gender.

2. The added player(s) must improve the team's performance at the table.

3. No added player played in an earlier stage of the event.

3. The team must notify the USBF Secretary, and the players must submit System Summary Forms and not add unusual bidding methods as they do when a change is made before the event starts.