When baseball commissioner Bud Selig in January of 2008 testified on Capitol Hill as part of the Congressional investigation into steroid use in sports, Fleischer was right by his side.
"Ari's advice on how to handle the press and deal with difficult communications problems has been of great value to me," Selig said of Fleischer, according to the PR firm's Web site. "Ari has helped me get ready for many major media events. He understands how reporters operate, and he uses that knowledge well."
This spring that knowledge will be put to the test once again as Fleischer attempts to help McGwire restart his career – and repair his tarnished image.
The first step in that effort came last month when McGwire tearfully admitted using steroids during his career, including during his record-setting 1998 season. Big Mac was officially a cheat.
"His goal was to become a batting coach and he wanted to get back into uniform and he knew he had to address the elephant in the room and he took it head on and he did it," Fleischer says.
"Mark deserves huge credit for coming forward, not having been outed but voluntarily – because he wanted to become a coach – coming forward and acknowledging what people suspected. He didn't need to do it, but he took it upon himself and told the truth, acknowledged he took steroids, and he apologized."
The day of McGwire's admission in January, recalls Fleischer, was a draining time for the slugger.
"It really wore him down. It was very difficult for him," Fleischer says. "His shoulders were slumped, he was really beaten-down, tired – and I wondered how this was all going to end."
But an outpouring of support soon boosted McGwire's morale.
"That night and the next morning he got so many text messages and e-mails and messages of support," Fleischer says, "when I saw him the next morning he was upbeat and chipper and he's been that way ever since."
"Because of all the great messages he got, he's held up so much better."
That support will be vital as McGwire returns to the national spotlight as soon as he steps on the diamond in Jupiter today.
"He couldn't wait to get to camp," notes Fleischer. "It'll be the first time he puts on the uniform with #25 on it again."
But returning to the batting cages will be easier for McGwire than restoring his reputation. The latter will not be an easy battle, but for Fleischer, it is just the latest challenge.
"When you look at the history of other players, everybody who's acknowledged [using steroids] went through a very hard time afterwards," he notes. "Immediately what follows is a genuine sense of disappointment among fans, a feeling of letdown. But there's also in this country a real feeling that people deserve second chances and I think that's what you'll see."
In between defending the Bush administration and founding his sports PR firm, Fleischer somehow found time to write a best-selling book about his time in the White House called "Taking Heat."
That is exactly what Mark McGwire will be doing this spring, but this time the fastballs won't be coming from the pitcher's mound – they'll be coming from a national audience full of critics. And it's up to Fleischer to help the slugger hit them out of the park.
"My sense of it is anybody who did steroids deserves a black mark because they did steroids – everybody, including Mark, and he knows that," Fleischer says. "But I also think when you see how genuine and sincere and apologetic he feels he doesn't deserve to be banished from this business for his whole life. He deserves a second chance. He's asked for one. My belief is that the fans are going to be happy to give him one."