Mark McGwire’s return to the Cardinals family should be great news for all involved. He is a historic figure in franchise history. He still has a passion for Our National Pastime, as evidenced by his impressive offseason work with current big leaguers.

But . . .

McGwire must air out the performance-enhancing issue once and for all. Only then can he go about his new job in relative peace.

As a private citizen living and golfing in Orange County, Calif., Big Mac could stonewall the issue for life. He could let his non-statements to Congress stand as his answer to all questions about the Canseco Era of baseball.

As a retiree, his past was the past. The whole PED discussion could continue on without him. It was none of his business.

As the new hitting coach of the Cards, though, McGwire can’t shrug off the issue. He is stepping back into the public eye. He is taking a high-profile job.

His face will be on camera all 162 games. The media will come calling day after day after day. This issue will hang over him day after day after day.

McGwire must take this head on. He can’t remain defiant, like Roger Clemens and Barry Bonds. He can’t offer mealy-mouthed recollections, as Alex Rodriguez did.

As A-Rod saw, that only made things worse. The media kept turning over rocks, looking for anything that might embarrass the tainted slugger.

Is that a road Big Mac wants to travel? Let’s hope not. That would be bad for him, bad for manager Tony La Russa and bad for a ballclub that doesn’t need the distraction.

Personally, I’ve come to terms with the Canseco Era. PED abuse was rampant. Hitters juiced up to hit home runs. It was good for business, so commissioner Bud Selig looked the other way -– as did the owners, general managers, managers, player agents and players' association leaders.

Pitchers juiced up to counter the hitters. Injured players juiced up to get healthy. Fringe players juiced up to reach and/or stick in the big leagues.

Many big-name players have been exposed as cheaters. Many more have avoided exposure, to this point.

PED abuse defined the Canseco Era. Fans and media types want to sort the dirty players from the clean, but that task is nearly impossible.

If everybody who played in this era took foolproof lie-detector tests, then we would finally know exactly what happened. Short of that, we’re just guessing.

These guys weren’t really cheating the sport. Absent a meaningful drug policy, baseball became the Wild West of chemical experimentation. Players had tacit approval to juice, so juice they did.

Many fans remain fixated on this “cheating.” They want to ban all the transgressors from the Hall of Fame and take away their statistical achievements.

I am more interested in seeing baseball move forward more intelligently. Athletes often ignore health risks while pursuing their competitive and financial goals, so it falls to the owners, general managers, managers, trainers, player agents and players' association executives to police the industry.

Most baseball players use workout programs to enhance their performances. Most players ingest training supplements to enhance those workouts. Moving forward, the industry needs to do all it can to prevent athletes from going overboard at the expense of their long-term health.

McGwire can play a part in all this. By coming clean, he can help educate everybody on what really happened -– and what must NOT happen again.

He has a great opportunity. If McGwire unburdens himself and dumps all the baggage, this hiring could be great for him, great for the team, great for the franchise and great for Cardinal Nation as a whole.

If he is “not here to talk about the past,” then the past will loom ominously over him and the whole organization for the duration of his coaching career.