Albert Pujols jogs to first after hitting a home run in World Series Game 3 Saturday. Getty Images

No matter who prevails in the World Series, Games 6 and 7 (if necessary) will be a poignant moment for St. Louis and its reigning superstar, Albert Pujols.

Pujols, a three-time MVP who has slugged 445 home runs and batted .328 during his 11-year career, also smashed three home runs in Game 3 in Texas Saturday night. He can become a free agent after the season. Flashbulbs popped throughout Busch Stadium when Pujols batted in the late innings of Game 2, as fans tried to get an image of what might have been his final home at-bat.

In 2004 Getty Images

But like a lot of aging sluggers—Pujols will be 32 in January—he is starting to resemble something of an opera singer as he gets older. Still massively strong with thick arms that look like they run a jackhammer all day, he's getting thick around the middle.

Clayton Skaggs, who has worked with Pujols and several other members of the Cardinals as the team's injury and performance consultant, said Pujols still has great strength and stability, especially through his core. "You shake his hand and you know immediately this is a person with some strength," Dr. Skaggs said.

But he also compared Pujols' strength and stability to that of a sumo wrestler. Certainly the Cardinals don't want Yokozuna Asashoryu manning first base for them in a few years.

Quick hands through the strike zone remains the key to good hitting, but a healthy back, hips and knees are vital, too. "Any physician will tell you as you get older if you're carrying too much weight it's going to put a lot of strain on your back, hips and knees," Skaggs said

Pujols is battling the same pitfalls every player does, including a profession seemingly designed to make players fat.

"These guys finish games at 10 p.m. and they're hungry," Skaggs said. "Their jobs virtually force them to eat late and not get enough rest."

That's a dangerous combination. Skaggs said outfielder Matt Holliday, Pujols' teammate, is fastidious about following a high-protein and low-fat diet, and lifting weights before games five times a week to prevent the weight that players put on during the season from turning to fat. Pujols he said, lifts about twice a week, and is less fastidious about his diet.

Frank Thomas, the massive retired slugger who played football at Auburn, battled to keep his weight down as he got older. He said fat guys can't survive in the game the way John Kruk, the famously rotund Phillies slugger, once did. "Too many guys are working too hard," Thomas said. "It's a different game now."

Pujols has declined to comment about anything but baseball since spring training, when talks between his representatives and the team broke down. He is seeking a deal similar to the one Alex Rodriguez received from the Yankees three years ago—10 years, roughly $275 million, plus potential bonuses.

The Cardinals, who want to maintain a payroll of about $100-110 million, would prefer to give Pujols fewer years and less money. "As far as payroll goes, I don't see a major deviation from where we are this year," Cardinals general manager John Mozeliak said Monday.