MLB The Show 23: How to fix the “Your opponent has an invalid roster” error in Mini Seasons and Moments
This doesn’t sound good.

There have been a few times in MLB The Show 23’s lifecycle in which a “Your opponent has an invalid roster” error popped up for users. If you’ve received this error message at any time, we can help. Here’s a look at how you can fix this problem.
“Your opponent has an invalid roster” in Mini Seasons and Moments
The “Your opponent has an invalid roster” error message has been a regular occurrence in MLB The Show 23 during the early parts of the game’s lifecycle. It first popped up in Mini Seasons in April 2023.
The development team quickly instituted a fix, but that only apply to new seasons that are created in MLB The Show 23. For those who had a season going in Diamond Dynasty prior to the implementation of the fix at that time, progress could not be restored. This meant that if you got that message, the only alternative to is to restart the entire season. This ultimatum was confirmed by the MLB The Show 23 team on April 7.
This error message popped up again in May 2023, as some players reported that it showed when attempting to do a Topps Now moment that was tied to Diamondbacks outfielder Dominic Fletcher. Because of this glitch, players were unable to access the moment.
San Diego Studios stated that a fix for that will be implemented on May 25, along with the content that is slated to go out on that date. Until then, players will have to sit tight.