What is this Reverse Mirror stuff
Credit for this goes to Nick Olson, who expanded and clarified my original explanation. Thanks Nick.

When the Big Ten signed their new TV deal with ABC/ESPN that started with the 2007 season, they successfully negotiated for all Big Ten games airing on ABC at either 12:00 p.m. or 3:30 p.m. Eastern Time to be shown on ESPN or ESPN2 in all markets where the game is not on ABC. In markets where the Big Ten game is on ABC, an alternate game will be shown on ESPN or ESPN2. So when you look at an ABC coverage map, find the game that is on ABC in your area. If it’s a Big Ten game, another game will be available to you on ESPN or ESPN2, and will be marked with ESPN or ESPN2 in the Coverage Notes section of my schedule. If the Big Ten game is not scheduled to be shown on ABC in your area, it will be available on either ESPN or ESPN2.

Important Note 1: These afternoon Big Ten games are NOT part of ESPN GamePlan, since the “Reverse Mirror” makes them nationally available (but see Important Note 2, below).

Important Note 2: There is no "Reverse Mirror" situation for the ABC Saturday Night Football games. As a result, if the Big Ten night game is not on ABC in your area, it will be available on ESPN GamePlan.

Important Note 3: The “Reverse Mirror” only applies to games played at Big Ten stadiums (Big Ten “home” games). Any neutral site games or games in which a Big Ten team is the “road” team are not guaranteed to be “Reverse Mirrored.” They might be, but they are not required to be under the Big Ten’s contract with ABC/ESPN.