The team hardly could have anticipated what has happened since.
In pitching a scoreless 10th inning on Monday, Isringhausen became the 23rd closer in history to record 300 saves, joining John Franco and Billy Wagner as the only men to do so in a Mets uniform.
"It puts him in the elite group of closers that have ever pitched in this game," Mets manager Terry Collins said. "And certainly he deserves it."
Like Wagner, Isringhausen recorded the bulk of his saves with other teams, joining the Mets already on the cusp of 300. But unlike Wagner, and even Franco, Isringhausen was a Met from his earliest days in the Majors, throwing his first pitches and recording his first save in New York.
That, more than anything, has helped transform an increasingly common milestone into a uniquely memorable one.
"It's kind of a cool story," Isringhausen said of coming full circle with the Mets. "The first one and the 300th."
Like so many of his saves, No. 300 was not without some requisite drama. After whiffing the first batter of the 10th inning, Isringhausen walked Padres second baseman Orlando Hudson and allowed a sharp single to Nick Hundley, putting two runners on base with one out. A groundout moved both men into scoring position, before Isringhausen finally induced Logan Forsythe to hit a game-ending groundout.
With that, Isringhausen pumped his right fist and slapped his glove with his hand, before descending into a mob of teammates on the PETCO Park field. Back in the clubhouse, they doused him with champagne, celebrating both a man and his career.
"If nothing else, it proves you've got to battle, you've got to hang in there," Collins said. "And he's the ultimate example of it."
For a long while, the road to 300 seemed stalled -- perhaps even closed forever. After tearing the ulnar collateral ligament in his right elbow two years ago, Isringhausen underwent his 11th surgery and struggled to work his way back to the big leagues. The Reds signed him to a Minor League deal last summer, but he did not pitch for them. They considered signing him again this spring, but passed.
More as a favor than anything, Ricciardi invited Isringhausen to Port St. Lucie in late February to throw a bullpen session. And suddenly, the old velocity was there. The signature curveball was there. And so, the Mets signed Isringhausen, stashed him in extended spring training to start the season and called him up to the big leagues shortly thereafter.
Upon trading closer Francisco Rodriguez to the Brewers last month, they then named Isringhausen the head of a closer-by-committee situation, hoping he might save some games and impart some wisdom to closer-in-waiting Bobby Parnell.
They believe he has done both.
"Everybody knows that he can get outs. Obviously, he's done it his whole career," Mets starter R.A. Dickey said. "I think his real value transcends his performance on the field. He offers much more than just getting the opportunity to close the game."
Now, with Isringhausen's 300th save come and gone, Collins said he will look to give others -- chiefly Parnell, but also Pedro Beato -- a chance to close out games as the Mets continue to search for their closer of the future.
"I'd like to keep watching him," Parnell said. "But when I get the opportunity, I'm definitely going to jump to do it, and take what he's taught me into it."
What Isringhausen has taught Parnell is to trust his stuff, no matter the situation. That, more than anything, is how Isringhausen recorded 300 saves in New York, Oakland and St. Louis: with conviction.
Afterward, in his typical style, Isringhausen jokingly referred to the whole business of 300 saves as "nonsense." But others might disagree. Within minutes of the milestone, Rodriguez texted his former setup man to offer congratulations. His teammates slapped him on the back and hugged him and shared champagne.
Isringhausen readily admits that his chase for 300 saves was one of the primary reasons why he returned to baseball this season, when he could have continued spending time at home. Now, he has achieved it, editing the record books and stamping an exclamation point on his career.
"It's been a long couple years for me," Isringhausen said. "It's nice. But I'm just glad it's over with."