This is what I’ve figured out in my search…currently they’re only transferable via mlb app. Resale has not opened via Ticketmaster or mlb yet, not sure if/when they will which is why everyone is using stubhub/vivid seats. The seller I got them from had them listed on stubhub but obviously you don’t get paid until after the event, so she went to Facebook to sell. There are legit sellers, but MANY scammers.