This team is just mentally screwed up. The weird unbalanced lineup they had most of the year messed with their 'clutch' hitting stats... but they've been so damned undisciplined and 'unclutch' in so many other important areas. The more important the job, the less likely it gets done, even if the player involved has the talent to pull it off. Closer, anyone?
I'm not going to call out anyone by name, because that would not be fair. It's most likely a group dynamic and not the fault of an individual player or players. Any players who could be considered guilty of 'choking' might have had no issues in a different setting.
This is going to make Luhnow's already very difficult job this offseason even harder. Not only will he have to plan moves to make up for deficits in talent (i.e. starting pitching), he's going to have consider making moves based on chemistry. With no guarantee that he guesses right. And if those moves come in the form of trades, the other GM's are going to bend him over the table if they get the slightest hint of what he's trying to do...
