If the game meets the requirements to avoid a blackout, that game MUST be shown in the primary network. MB is a primary market for Carolina because they are the nearest team. Every team has a primary market and the two main networks on Sunday each get double header days assigned before the season starts. That's up to the local affiliate, not the team.
They have NOTHING to do with choosing what games actually air.
The visiting team decides which network if the schedule allows it.