That baseball card now pictures a friend, a mentor and a hitting coach who has left an indelible stamp on a Cardinals offense that has taken to a rather simple hitting philosophy that emphasizes mental approach over mechanical tweaking.
"We wouldn't have our numbers that we had this year without him," David Freese said of McGwire, St. Louis' second-year hitting coach. "He's extremely intelligent, and I think the one thing that a hitting coach needs to have is feel. And that's what he brings to the table. He knows when to kind of push a little bit. He knows when to pull back and let us do our thing."
The Cardinals' frenetic September run was credited largely to the rotation, which posted a 2.85 ERA during the season's final month. The bullpen stole much of the credit when the team then made a push through the first two rounds of the playoffs.
Absent from the spotlight through much of this has been the offense, though the lack of appropriate acknowledgement comes from the fact that this group has been producing all along. A lineup that McGwire helped mold into one of the National League's best during the regular season has been one of the postseason's most prolific as well.
Despite scoring just four runs in the first two games of this World Series, the Cardinals still hold a postseason-best .276 team average, and they have averaged more than five runs per game. That's more than the Rangers, whose lineup has been lauded as the most loaded.
Having a future Hall of Famer in Albert Pujols -- and a pair of All-Stars hitting behind him -- certainly is a built-in benefit for McGwire. But the work he's done, in particular with some of the club's younger hitters, has been on display for a nationwide audience all month.
"Coming into Spring Training, there was just a calmness about them," McGwire said of the up-and-coming hitters. "They understood their position. They got ready better. The communication amongst hitters is unbelievable this year. You have to take everybody for what they are."
His hitters will attest to the fact that McGwire has come into his own as a hitting coach in 2011 after learning from the experience of last season. There is also ubiquitous respect for McGwire's ability to mesh with hitters of varying experience levels.
"I think the good thing is that he's the same guy with Albert and [Daniel] Descalso," Schumaker said. "He knows what works for guys. Some guys need a lot of stuff, and some guys don't need anything. That's what he's very good at is identifying that."
Schumaker's relationship with McGwire is a particularly unique one. Since seeking personal instruction from the former slugger after the 2006 offseason, Schumaker has spent time with McGwire each winter since.
He lobbied for McGwire to be named St. Louis' hitting coach after the '09 season, and came to quickly realize that McGwire's suggestions would work even for those who didn't follow in the former slugger's power mold.
So, too, did outfielder Matt Holliday, another one of McGwire's regular offseason pupils in California.
"He did a good job of giving his past experience and some of the things that helped him," Holliday said. "We talk a lot about approach and what particular guys are doing. He gets it."
McGwire's game plan is to, most importantly, have one. He believes there can be such a thing as too much dependency on technology, but not too much preparation. He sends his hitters up with the mindset that they're going to swing at every pitch. That, McGwire says, allows for better mental acuity.
He preaches strike zone discipline and emphasizes that his hitters focus on only one part of the plate. It's all about having a plan for a pitcher, and when it comes to making adjustments, McGwire prefers a focus on the mental than the mechanical.
"I was surprised at how quickly he got into the art of conversing, relating, getting across his points," said manager Tony La Russa, who spent several years trying to get McGwire to rejoin the organization.
"You learn how to make those points, and it was so natural for them that, I mean, I watched in the second year, guys go to him because he's so understanding and he knows how hard it is. He's a heck of a lot more understanding than I would be."
The product of all this has been production. Not only did the Cardinals lead the National League in batting average and on-base percentage this season, but they also cut down on strikeouts and increased their walk total.
The club finished tops in the NL in runs scored and was the only one in the league not to strike out more than 1,000 times.
"There is always fine-tuning with your mechanics, but there is a reason why you're here," McGwire said. "I've always enjoyed talking hitting. I've always enjoyed teaching hitting. I'm very happy that Tony asked me to come back. I'm thoroughly enjoying it."
He's enjoying it on this stage, too.
A three-time World Series participant, McGwire made all those appearances during the first five years of his big league career. The last came in 1990 when, as McGwire will tell you, a scouting report consisted of merely a piece of paper.
Much has changed since then. Including his legacy.
From then until now, McGwire has transformed. From owner of baseball's single-season home run record to admitted user of steroids, McGwire's career has been spotted with both awe and disdain.
Now, though, he is just a hitting coach, a man drawn back to a game that he loved and eager to share all he has learned from it.
"Last year, he had a lot of different issues to take care of during the offseason than this year," Schumaker said. "But you never knew that coming to the field. That's what so many guys respect about him. He never brought that up.
"Hopefully people can kind of turn the page on that. It's time to see past that. They have to see that he's a very good hitting coach."