But when it became clear to Isringhausen last September that he was simply physically incapable of doing his job, he knew it was time to shut things down for a while. The day after his last successful outing of 2006, Isringhausen endured his last unsuccessful one. Soon thereafter, he called it a season and underwent surgery to correct an agonizing hip condition.
"I threw that one day in Washington [Sept. 5] and got the save," Isringhausen said, "and the next day, I went out and started warming up, and I was like, 'Oh boy.' That's when I knew.
"I can deal with criticism and I can deal with booing. The time when I decided to quit was when I decided I wasn't helping anymore. I was doing more harm than good."
But Isringhausen never seriously considered hanging it up for good. The possibility existed that his hip might force him to retire, but he wasn't ready to do so voluntarily.
He's glad he stuck with it, because as Spring Training 2007 gets started, Isringhausen is excited for another chance at doing his old job. The man who holds the Cardinals' career saves record didn't get to close out any postseason games.
He delighted in his teammates' success, and took some pride in helping young Adam Wainwright adjust to the pressures of closing games. But that doesn't mean it was fun to watch someone else do his job.
"I was happy for the organization and happy for these guys because you only get so many chances," he said. "And for a kid like [Wainwright], who's just a wonderful kid, he had a good year -- getting married, having a kid and winning a World Series. I told him, you don't have anywhere to go but down.
"But I'd rather be out there pitching."
The troubles in his left hip, a condition that dates back as far as 2002, kept him from finishing his delivery with any consistency. That meant major command problems, which led to the most walks, most home runs and most blown saves he'd ever allowed since becoming a reliever.
With the injury surgically repaired, Isringhausen is feeling better than he has in three or four years. He's being brought along slowly, but expects to be available to close games for St. Louis starting on Opening Day. And he's thinking about pitching beyond 2007, as well.
"If things stay the way they are, yes, I'll pitch again," he said. "If I scuffle again all year, I probably won't. If I scuffle again all year, I probably won't finish the year. But if things keep feeling the way they are now, I'll pitch again. Where, I don't know. Maybe here, maybe somewhere else."
St. Louis holds an option on Isringhausen for 2008 valued at $8 million. If the right-hander looks like a viable and effective option in the ninth inning, that might be a decent value. If he struggles, the option surely won't be picked up.
The expectation of the Cardinals field staff is the former, not the latter. Manager Tony La Russa and pitching coach Dave Duncan are counting on him to be the linchpin of a deep bullpen.
"The results that he will give will be good," Duncan said.
By his standards, Isringhausen did not give good results in 2006. He saved 33 games but took 10 blown saves and eight losses, and he permitted 10 home runs. He sees no reason for that to be the case again in '07.
That led to constant calls for someone else to close games. Isringhausen was booed vigorously at home, even as he tried to pitch through a debilitating condition. It didn't sit well with him, and it greatly upset teammates and coaches.
"I think he really pushed it as a hero," La Russa said. "That's why I think he deserves so much credit, because he really was the answer in that bullpen. It really wasn't a good thing to have to go a different way.
"We knew that he was laboring, but if you look, there was a year or two there where he got 40 saves and he hadn't been healthy. So we're kind of used to seeing him be less than 100 percent [and still succeed]."
Isringhausen swears that the criticisms he heard are no motivation going forward.
"I want to prove to myself that I can still get people out," he said. "I got people out last year on one leg. I have to think I can do better with two. I had a down year for me, but I've seen worse. And that was on one leg."
His delivery gets closer to right each time he throws. It's early in the spring, but consistency in his mechanics seems to be an attainable goal.
"I'm having to almost restart things, because I've gotten into some bad habits the past few years with my hip, throwing weird," he said.
"That's what I'm working on now, is a consistent delivery. Once I do that, all my pitches will start falling into place and it's good times ahead."
Matthew Leach is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.