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.
It's widely assumed that Jason Isringhausen will not return to the Mets in 2012.
With that said, the Mets would have been wise to experiment with their bullpen for the remainder of this season in order to better dictate roles for 2012.
The main cog of this experiment would have been Bobby Parnell, who would have inherited the closer role with both Francisco Rodriguez and Isringhausen departed.
Parnell, who's been tabbed as the closer of the future, would have been able to garner some valuable experience in the role while pitching in a less pressure-packed atmosphere with the Mets on the fringes of the playoff picture.
Now, the best-case scenario for the Mets is that they start to win, meaning Isringhausen stays in the primary closer role.
For Parnell, that does little for his development, as he'll need to start logging some innings as the primary closer in order for the Mets to evaluate his potential as their future late-game stopper.
With all of the injuries that Jason Isringhausen has endured throughout his career, it's a wonder that Sandy Alderson didn't trade the former "Generation K" member while his stock was at it's highest.
Izzy has been healthy since his call up in April after suffering an elbow injury during the final days of spring training. As a pessimistic Mets fan, you'd have to think that streak of good health will only last for so long.
Eventually, age will set in on Isringhausen, who's on pace to throw his most innings since the 2008 season.
We've already begun to see the 38-year-old's age set in, as he's blown consecutive saves in his last two outings.
It's hard to knock Sandy Alderson's body of work since taking over as the Mets GM, but his desire to hold on to Jason Isringhausen through the trade deadline may prove to be his one blemish of 2011.
Hey, there's still the waiver-wire.