David Brown at Big League Stew provides a transcript of the McGwire/Costas interview with running commentary. This is the question I was looking for Bob to ask:

BC: This is from Jose Canseco’s book: “What we did, more times than I can count, was go into the bathroom stall together to shoot up steroids. That’s right after batting practice, or right before a game. We would load up our syringes and inject ourselves.”

MM: There’s absolutely no truth to that whatsoever.

BC: Why do you think Jose would say that?

MM: He had to sell a book.

BC: So that didn’t happen in the clubhouse?

MM: Absolutely not. I couldn’t be more adamant about that.

Sorry, Jose has been right about too many things in that book. I believe Jose more than Mark on this one.

The other thing that sticks out to me is this:

Bob Costas: When did you first try steroids?

Mark McGwire: I was introduced to steroids [in] the gyms you worked out back in the day. It was readily available. Guys at gyms talked about it. I believe it was the winter of ’89 into ’90. I was given a couple weeks’ worth. I tried it, never thought anything of it, just moved on from it. As far as using it on a consistent basis, the winter of ’93/’94.

Take a look at McGwire’s career and make your best guess as to when he started using PEDs. I’d peg it after the 1991 season. He had gone four years without the power he showed in his rookie year of 1987 (which was a big home run year, for some reason). Worse, he was going through his prime declining, and his 1991 season was poor for a power hitting first baseman. Then in 1992, he takes off, one year before the big offensive surge in baseball. Wikipedia credits a new, fearsome look. In my opinion, 1992 is the line in the sand.