After the Mets dealt Francisco Rodriguez prior to the trade deadline, Isringhausen became the de facto closer due to his experience in the role.
But for a moment, put yourself back in time to before the July 31st trade deadline, and before Isringhausen became the poster child for yet another beleaguered collection of arms in the Mets' bullpen.
The veteran right-hander was rumored to have drawn a great deal of interest from contending teams, but Sandy Alderson retain Isringhausen just in case the Mets made a late season playoff push.
In retrospect, that decision appears to have been ill-fated.
Let's take a look at the two main reasons why the Mets will regret not moving Jason Isringhausen at the trade deadline.