I was disappointed about this too and I emailed MLB and like you read earlier, they don't support the Evo 3D now.
I don't get it, it runs the same version of Android as the supported devices, right?
Hopefully, they'll see the feedback on the Android Market comments and support it ASAP. How difficult can it be to approve it for the Evo?
Of course, I can use my Slingbox to watch MLB Network as well as YES, SNY, Fox and TBS when they air games.