In particular, Fisk, who split his career between the Red Sox and White Sox, fumed at McGwire's notion that steroids didn't help him hit a then-record 70 home runs in 1998.
"That's a crock," Fisk said in an interview with the Chicago Tribune. "There's a reason they call it performance-enhancing drugs. That's what it does -- performance enhancement. You can be good, but it's going to make you better. You can be average, but it is going to make you good. If you are below average, it is going to make you average. Some guys who went that route got their five-year, $35 million contracts and now are off into the sunset somewhere. Because once they can't use [steroids] anymore, they can't play anymore.
"And steroids, during that time, probably did as much to escalate players' salaries as did free agency, as did arbitration, and all of that stuff. It did more than just put home runs up on the board or money in the guys' pocket."
McGwire said in several interviews that his sole reason for doing steroids was to help the healing process from injuries. Fisk, who played 24 years in the Majors and set the record for most games caught, also scoffed at that line of thinking.
"Try having your knees operated on and catching for 30 years," Fisk said to the Tribune. "Do you think you feel good when you go out there? [McGwire] had to stand around and play first base. So excuuuuse me."
Fisk, who retired from the Majors in 1993, hardly made McGwire his lone target. He blasted the culture of the entire "steroid era," saving some of his harshest words for Roger Clemens, the seven-time Cy Young Award winner who was prominently featured in the Mitchell Report with accusations of steroid use, but has continually been fierce in his denial that he ever used PEDs.
"The reason he got let go from the Red Sox was because he was starting to break down," Fisk told the newspaper. "His last couple of years in Boston just weren't very productive, a la 'The Rocket.' Then all of a sudden he goes to Toronto and he wants to show somebody something. Then he gets two consecutive Cy Young Awards [in '97 and '98]. Come on, give me a bucket.
"It's obvious to players. You notice that stuff. You know how hard it is to play the game. You know how hard it is to be productive at any age, but especially at an older age. You see guys who are as productive later on as they were early [in their careers]. It offends guys that stayed clean. But [the abusers] set their great, great, great grandchildren up for the rest of their lives."
Fisk wishes that steroid users would have been called out long ago. He also thinks those who used should have shown remorse long before now.
"[Non-prescription] steroid use has been a federal offense for a long time, regardless of whether baseball was recognizing it and putting rules into place," Fisk told the Tribune. "The people who did it ... they were breaking the law to start with. It doesn't have to be a baseball law. They knew what they were doing and the reason they were doing it. Now they are sorry because they are getting called out."
If anyone was surprised when McGwire -- entering his first season as hitting coach for the Cardinals -- confirmed he was a steroid user, Fisk thinks they must have been extremely naïve.
"I didn't just find this out," Fisk told the Tribune on Tuesday from Florida. "I worked hard in the gym to look like I did and feel like I felt. [Catching] took a toll on me, too. A lot of people knew. Nobody wanted to really address the issue.
"But when you have some of these obscene numbers being put up by people who shouldn't even be there. ... I mean, you know what's going on. ... The people it should have been most obvious to are the people who covered it up by not addressing it."
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.