Mark McGwire, left, has thrived in his work with Tony La Russa, Albert Pujols and the rest of the Cardinals. (Greg Fiume/GETTY IMAGES)

He sits almost anonymously on the periphery of this World Series, like the parking lot beyond center field at Busch Stadium in St. Louis — the parking lot where the old Busch Stadium used to stand, the stadium where Mark McGwire once ruled the sport, the sport that, after a long exile, welcomed him back two years ago. Like that parking lot, McGwire is here now for his utility, not his glory.

As the World Series shifted to Texas on Friday, a workout day prior to Saturday night’s Game 3 between the St. Louis Cardinals and Texas Rangers at Rangers Ballpark, McGwire, the Cardinals’ hitting coach, made the rounds of his hitters, bouncing from the indoor cages to the outdoor one, watching video, tossing balls in the paths of bats, offering suggestions.

After slugging their way through the first two rounds of the playoffs, hitting .288 collectively and scoring 62 runs in 11 games, the Cardinals have slumped to a .203 batting average and a .254 slugging percentage in the first two games of the World Series, scoring just four runs. But this is no time for McGwire to start overhauling anyone’s swing. His message to his hitters, typically, is to have a plan and trust your swing. That is unlikely to change this weekend.

“You get to this level, it’s all mental,” McGwire, 48, said before the series began, his famous blue eyes as piercing as ever, but his once-red goatee now a stark white. “There’s always fine-tuning with your mechanics, but there’s a reason why you’re here: You have good mechanics. You know how to hit. And then in order to stay here for a long period of time you have to understand . . . this game is mental.

“Thirteen different hitters, 13 different plans” he said of his troops.

That he is here at all, back in uniform, is a function of the loyalty of Tony La Russa, the Cardinals’ manager, who wanted McGwire as his hitting coach for his insight and teaching skills, but it is also a function of the public’s capacity for forgiveness and the redemptive power bestowed by the passage of time.

“He had a passion to coach,” La Russa said recently. “That’s why I kept inviting him to come to spring training [in previous years as a special instructor] — because I knew he had a lot to share. I wasn’t surprised he had a lot to offer. I was surprised at how quickly he got into art of conversing, relating, getting his points across. Guys go to him because he’s so understanding and he knows hard how it is.”

It was revealing that, during a 30-minute media session the day before Game 1, McGwire fielded dozens of questions, but none were about the dark issues in his past — the infamous 70-homer season in 1998 that was later tarnished by steroids revelations, the 2005 appearance on Capitol Hill when McGwire deflected questions from congressmen about steroids use, and finally, his 2009 tearful admission, prior to his hiring by the Cardinals as hitting coach, that he had used steroids extensively during his career.

Perhaps no one asked the question because no one wanted McGwire to get sidetracked from his steady stream of insightful answers about the craft of hitting. Perhaps no one had the heart to shift the conversation from a topic he loves to one he loathes. Or perhaps it — the steroids question — is simply no longer germane to the McGwire story, let alone the story of the 2011 Cardinals.

“The fact he was so honest [about steroids] when he got to spring training [in 2010] — he sat there for three days and took questions until no one had any more — he exhausted that chain of questions,” Cardinals General Manager John Mozeliak said. “Now, when you see him in season or under the microscope here, he’s available” to the media.

It is impossible to know precisely the extent of a coach’s influence. The players are the performers. They deserve the credit. But the Cardinals’ team batting average has gone up in each of McGwire’s two seasons as hitting coach, as has their total number of walks, while their strikeouts have gone down. This year, the Cardinals had the highest batting average and OPS (on-base plus slugging percentages) in the National League, as well as the fewest strikeouts.

“That’s not a coincidence,” said Cardinals third baseman David Freese, who grew up in Missouri and had a poster of McGwire on his bedroom wall during the memorable summer of 1998. “I know for me, he’s a big reason I’m able to do what I’ve done. He knows me as a hitter. He keeps it simple. He can jump on [flaws] real quick — mechanical, mental, confidence-wise.”

A big part of being a coach is subordinating one’s ego in the interest of others. A hitting coach often carries the bucket of balls from the equipment room to the batting cage. He grabs a knee and soft-tosses to his hitters whenever they ask. He arrives early, stays late. For McGwire, this came easily, Cardinals insiders say, because he is shy by nature and was always uncomfortable with stardom.

“He never makes it about himself,” Freese said.

Naturally, McGwire has formed a special bond with Albert Pujols, the Cardinals’ slugging superstar, whom McGwire first met when the latter was a 21-year-old rookie in 2001. Ten years later, Pujols, who is in his final days before reaching free agency, is widely acknowledged as the premier hitter of his generation, and his 445 career home runs are only 138 behind McGwire.

“Number 5 is probably the strongest person mentally I’ve ever been around,” McGwire said of Pujols. “This year, with all the stuff he had to deal with in spring training — free agency, not doing the contract [extension], getting off to a sort of a rough start, and having injuries and dealing with everything he had to deal with — for him to put up the numbers he did you have to be strong mentally.”

And then McGwire got on a roll, talking about Pujols as a rookie (“It’s not hard to recognize greatness,” McGwire said), the importance of the mental side, the craft of hitting, the art of finding the right pitch to hit. It seemed as if he could have gone on about it forever.