Baseball is finally back, and my Tivo Stream has no access to the MLB.tv app.
Bummed.
any suggestions besides casting from a chrome tab on my laptop?
To be more clear, it sounds like you're looking for the MLB app in the list of integrated and "search supported" apps within the TiVo Stream 4K ecosphere. These are only apps TiVo has partnered with to get content aggregated into their Stream app, but that doesn't mean you can't find and install/load more through the regular Google Play store. They just won't have the same integration and aggregation.
Hit the circle button on the mid left of the remote to go to the main Android Home screen. Then find the Google Play store in the top row, click on it and search for MLB.TV. It may still be in the "Featured Apps" right there when you open it, as glossed over unhelpfully above.
Play ball!!!