MLB general managers are skeptical—even paranoid—when constructing their teams. They prepare for adversity, but each has a potential nightmare that would be impossible to deal with.
Just one injured player, underachiever, flawed philosophy or environmental effect could derail a club's season. Many of the following hypothetical scenarios would impede competitiveness beyond 2013, too.
Though none are certain to unfold, all of them could realistically happen.
Every executive fears the factors that they can't control.