Exclusive: The man behind the Max

As the Justice Department pursues its perjury investigation of Roger Clemens, Jose Canseco may put his credibility at risk during a scheduled interview with federal agents next week if the author of Vindicated discloses the identity of "Max."

Canseco uses that pseudonym on page 184 of his latest book to describe the personal trainer and alleged steroid pusher whom he claims he introduced to Alex Rodriguez. In a Miami-area restaurant on Tuesday night, trainer Joseph Dion read the passage in front of two SI reporters and instantly identified Max.

"That's gotta be me," Dion said.

Dion said that Canseco is partially accurate in his portrayal of Max. Yes, Dion is a Canadian-born trainer who knew Canseco during his Toronto Blue Jays days. And it's true that Dion moved back to Miami, where he was raised, and was introduced to Rodriguez by Canseco in the late '90s. Dion said he worked with Rodriguez for four years when the current Yankee played for the Seattle Mariners.

But Dion adamantly denies Canseco's written account of Max as a "fan of steroids" who began working with Rodriguez specifically to juice the young phenom's body with illicit performance-enhancing drugs.

"That's really, really funny because I am the one person that hates steroids," Dion said. "I'm against it 100 percent. And, A-Rod, at the time that I trained him -- and this I swear to God -- was 100 percent against steroids. He was one of the hardest working guys, and most natural guy, that I've met in my life. He hated steroids. We talked about it."

With a shaven head and wearing a skin-tight Under Armour shirt, Dion looks lean and toned but not overblown. Nearing age 50, he remains a trainer in South Florida who works in a gym in a strip mall. He maintains a client list that includes housewives, prep athletes and two or three pro players.

The contradictions between Dion's and Canseco's stories are important, not just to the authenticity of Rodriguez's march through baseball history, but to federal investigators who have been trying to unearth steroid users and suppliers since agents raided BALCO in 2003. Whether investigating Barry Bonds or Clemens or Olympic stars and coaches, determining the credibility of witnesses is essential in the government's sweeping steroid investigation of sports.

On Friday, Canseco returned a call from SI regarding Dion's claim but said, "Ask him to call me. I want to talk to him before I comment on it." An associate close to Canseco confirmed that Dion is "Max" in the book.

Dion said that to this point no one -- not Canseco, federal agents, Major League Baseball, the book's publisher, Simon Spotlight, or Rodriguez -- have contacted him since the release of Vindicated.

If investigators ask to interview him, Dion said he would agree.

"I'm clean," he said. "I have no reason for concern."

By his account, Dion is a simple fitness devotee and instructor who runs five miles a day, eats brown rice with his sushi and doesn't push protein powders on his clients, much less steroids. If Dion is telling the truth, why would Canseco fabricate a steroid identity for him?

"I'm hurt in every way because it's not right and it's not true," Dion said. "I don't know if he is [writing Vindicated] for business or for fame or what."