Pjrm68 - agree. I found on an apple blog site (can't remember which one) the list of compatible apps, MLB was listed as coming soon. Maybe they will have it ready to roll out by opening day. I hope they will allow video (highly doubt it) but would be nice to watch a ball game on a long road trip.
I wouldn't hold my breath on that. I do not think there is any possible video transfer via Lightning cable alone. Additionally, playing video goes against CarPlay's sole purpose - a "safer" way to harness your phone's capabilities while driving. I really wonder what MLB At Bat will do in CarPlay. Maybe just audio, like all other CarPlay apps so far (except Maps).