That makes sense for Michigan, but not for Michigan State. Michigan measures itself by Ohio State, but Michigan State measures itself by Michigan. Who else would be Michigan State's protected rival? I'm not a Michigan State fan, but from the outside I can't think of any team other than Michigan that MSU pines away to play. And when you factor in who the other teams have as natural rivals, who would lose their protected rivalry? The problem is that MSU fits into the middle stratum of the B1G teams, so it makes more sense to have a natural rival in that same range, but does MSU care about Illinois? Minnesota, Wisconsin, and Iowa already have their triumverate--can't plug MSU in there. Purdue and Indiana seems straightforward. And Penn State is too good a team (and without a long-term rivalry) to pair with MSU. So who else for MSU?