A) What The Machine is doing is removing one player at a time from your roster and determining how dramatically losing that player without replacing him hurts your probability to win. It is likely that you only have one defense, but you have a backup quarterback. There is no need to be concerned about this being seemingly off. The Machine is able to understand that some positions have more value than others. For example, The Machine will see that there are plenty of defenses available on waivers, but not great quarterbacks, so in reality, The Machine will understand that QBs are more valuable than defenses.