Baseball fans can be a forgiving lot. Ask Jason Giambi, who recouped much of his icon-in-good-standing status after issuing a generic apology for unspecified indiscretions. Ask Orlando Cepeda, who rode a tightly focused publicity blitz into baseball’s Hall of Fame after serving time for pot smuggling.

Ask the Pittsburgh Pirates, still in business after 17 consecutive losing seasons.

It doesn’t take a Ruthian effort to curry favor. A halfhearted apology. The pretense of good intentions. It’s called playing the game.

Now batting: Mark McGwire, returning to baseball as the St. Louis Cardinals hitting coach after years of self-imposed, gated-community exile.

McGwire, you’ll recall, had quite an aptitude for playing the game between the foul lines. He was Rookie of the Year, a 12-time All-Star, won a Gold Glove, averaged 50 homers and 122 RBI per 162 games during his career. Along the way he developed a deep understanding of the art of hitting a pitched ball. When Matt Holliday showed up in Oakland last spring for his cameo appearance with the Athletics, he raved about the personal instruction McGwire had given him during the offseason.

So Tony La Russa and the Cardinals have made a fine hire. But this discussion isn’t about

McGwire’s credentials. It’s about his credibility.

For all his achievement, he never warmed to the game away from the field. He preferred not to talk about himself. He declined to partake of the buzz he helped create. If someone could have found a way to play baseball in a bell jar, you sense he would’ve loved that — just him and the game, with no buildup or after-party.

But it wasn’t that way, and isn’t today. Thus, he returns to a game and fans curious to hear what he has to say for himself. Because the last time they saw him, at the height of the steroids witch hunt, he was melting down before a congressional panel.

Look, there’s no getting around it. It is widely presumed McGwire used performance-enhancing drugs during his career. We know he used andro in 1998 — a banned substance now, but not then — on his way to breaking Roger Maris’ single-season home-run record. We know he morphed from a skinny rookie (listed at 215 pounds in the A’s 1986 media guide), to Popeye, to Paul Bunyan. Former teammate Jose Canseco, in one of his literary triumphs (“The Cat in the Hat Gets Ripped on Deca-Durabolin” if we’re not mistaken), claimed firsthand knowledge of McGwire’s steroid use.

The witch hunt has cooled since McGwire’s appearance on Capitol Hill. But fans, though suckers for a half-baked mea culpa, still display a low tolerance for what they perceive to be drug cheats. Given all of the above, how then does McGwire re-assimilate himself into the baseball culture?

He could refuse to talk about the past, but he’s already been hoisted on that petard.

He could refuse to talk at all, ever, to anyone outside the Cardinals family. But the silent treatment hasn’t served him that well over the past few years.

He could agree to discuss contemporary baseball matters only, but that kind of qualified premise never holds up.

He’d be better served to reflect on what Alex Rodriguez has been through this year.