Making his first appearance for the Mets since July 31, 1999, Isringhausen recorded a pair of outs to strand two inherited runners in the seventh inning to preserve a 4-all tie. It was his first game with the ballclub since being traded with Greg McMichael to Oakland for Billy Taylor at the trading deadline nearly 12 years ago.
The 11-year, 254-day gap between pitches for the Mets was the largest gap in franchise history, according to the Elias Sports Bureau.
Isringhausen and fellow right-handed reliever Ryota Igarashi were activated Monday to offset a bullpen that has now logged more innings than any relief corps in the National League.
"My heart was pumping a little bit," Isringhausen said. "But I've always told myself when I don't feel that way, I don't want to be here anymore. I was nervous. But that's what makes it fun. I told them I'm ready whenever the phone rings, whenever they want to use me. I got used tonight. I got through it. And tomorrow's another day."
The previous franchise record holder was Bob Miller, who went 10 years, 362 days -- from Sept. 29, 1962 to Sept. 26, 1973 -- between Mets pitching appearances. David Cone is next at 10 years, 224 days (Aug. 23, 1992 to April 4, 2003).
Isringhausen's return ranked as the longest gap in Major League Baseball since Doug Brocail returned to the mound for San Diego on July 14, 2006, 11 years, 346 days after his last appearance.
Isringhausen had been injured the past two seasons, so he had never stepped foot into Citi Field before Monday's activation.
"It's just another ballpark to me. But to put the 'Mets' across your chest, it's pretty special," he said.
Isringhausen insisted he could not remember pitching in relief at Wrigley Field for three innings the day he was traded to Oakland at the deadline in 1999. He only remembered getting called into a meeting with then-general manager Steve Phillips.
"I don't remember what city it was in or anything like that," Isringhausen said. "... There have been a lot of games between then and now."
As for the trade to Oakland, he initially was disappointed, since he was getting dealt by his original club. But it clearly worked out. Now 38 years old, he has amassed 293 saves.
"I talked to [Oakland GM] Billy Beane that night and he said, 'You're going to be a closer,'" Isringhausen recalled. "... It was one of those things where you got traded from your first team. It was hard, but I wouldn't change the path of my career for anything. And now I'm back and just happy to be here."
In a sense, the trade launched his career.
"They talked about me being a reliever here, but with [John] Franco, and [Armando] Benitez was here at the time, I didn't really want to be a middle man," Isringhausen said. "And that's what I became after I tore some scar tissue after a side session coming back from Tommy John [surgery] in '99. I worked out of the bullpen for a little bit, and then I think I was just the odd-man out."
Isringhausen had agreed to wait in Port St. Lucie, Fla. for up to two weeks while the Mets tried to find roster room this season. Asked if he was confident he would eventually join the club, Isringhausen replied: "If we hadn't had a couple of extra-inning games and the starters were going eight innings, they probably wouldn't need me. There was always that doubt. But, in the same sense, I knew if arms got extended a little bit, there would be a chance for me to get here. Not that I wished ill-will on anybody, but it happened sooner than later."