You know where Cardinals fans stand when it comes to re-signing Albert Pujols. (Christian Petersen/GETTY IMAGES)

What if Lou Gehrig and Jimmie Foxx in 1934, or Ted Williams and Stan Musial in ’49, or Mickey Mantle and Willie Mays in ’62, or Hank Aaron and Frank Robinson in ’65 could’ve said, “I wonder who I’ll play for next year?”

The times weren’t ripe then, but they sure are now. That’s where Albert Pujols, 31, and Prince Fielder, 27, stand as their teams play for the National League pennant. They are the play within the play.

These two are not just stars that are free agents. They both embody their teams, the Cardinals classic and traditional, the Brewers burly and proud to be a bit scruffy. Their personalities are the core of their franchises. As a result, romantics say that one or both may return to their old teams. Yet that’s very seldom how it works these days. Free equals “Going, going . . .

Before this season, Pujols already turned down a Cards contract reportedly for nine years and $195 million. So, the bidding for him presumably starts at 10 years and far more than $200 million. Fielder, who said recently that this was probably his last year as a Brewer, may slipstream right behind Pujols with agent Scott Boras doing the arm-wrestling.

The stakes truly are as high as they seem because Pujols and Fielder have been genuinely great — so far. Gehrig, Foxx, Aaron, Mays, Mantle and Robinson are six of the 10 players, along with others such as Ken Griffey Jr., whose careers most resemble Pujols statistically at 31. Just obscure guys.

Fielder needs a few years to join that company. So far, his progress is “only” comparable to Hall of Famers like Eddie Murray, Jim Rice and Orlando Cepeda.

With this NL Championship Series tied at two games apiece after a 4-2 Brewers win on Thursday night, the stage is perfectly set for this pair. Pujols took the early lead with five extra-base hits in the first three games. But Fielder has caught him after a walk, double and crucial dig of a low throw at first base. Both have easy slugging percentages to remember: exactly 1.000.

After Fielder smoked his double to center field in Game 4, a hush and buzz spread over packed Busch Stadium, as if to say, “Well, it wasn’t a home run.” The youngest man ever to hit 50 homers, the slugger with 200 bombs in the last five years, was simply too good to haze. Here was, possibly, 275 pounds of greatness hitting its prime. Please, let him go anywhere except the NL Central and especially those hated Cubs.

Every time Pujols came to bat, animals were sacrificed and blood covered the moon. Well, not quite. But a lot of people yelled, “Please don’t go, Albert,” because the Cards’ first baseman is the most nearly perfect player a lot of them are ever going to see.

Yet, amid this adulation, a morsel of respectful realism is needed.

Long ago, when players were serfs, decisions were few. And things were also less fun. Imagine: What if the teams that developed stars like Double X and the Iron Horse, or the Splendid Splinter and Stan the Man, had to decide whether to keep them and at what price?

Then, no one had to venture a nervous answer. Now they do. And there is a precarious balance between the intrinsic value of these two players and the astronomical prices they will soon command. Some glamour teams like the Yankees, Red Sox, Phillies and Angels are set at first base. But the Cubs, Rangers and Giants have money and needs. The Marlins, with their new $515 million stadium, are talking bravely. The Nationals might even overlook the existence of a one-year Adam LaRoche deal to add Babe Ruth for a decade.

But there’s a tripwire. The rate at which players age and lose their skills is a mystery. Using Pujols as an example, here are the flip sides of the truth.

Everything he has done up until this moment, including 445 homers, is consistent with a man who may actually rival any (non-juiced) player except Ruth himself. What was age to the Babe? From 32 through 37, he averaged 49 homers and 152 RBI a season. If he could do it, living as he did, why couldn’t Pujols? Also, Aaron, after he hit age 32, had seven seasons when he hit more than 30 homers. So, there are two “Sign Pujols” examples. Albert’s never had fewer than 32 homers in any of his 11 seasons. Why would he start now?

But here is the other side of the coin and it’s a sobering one. Among the players who profile most like Pujols, how many would have been worth a 10-year contract at his age? How many times, for instance, did they have more than 30 homers in a season after they reached that age? Here are the answers: Mays did it four times, Gehrig only twice, Foxx, Frank Robinson, Mantle and Griffey only once each and Mel Ott never. Hard to believe.

Aaron, with seven such years, would’ve been worth it.

So, think hard about it: Pujols for 10 years starting at 32. From that point, Ted Williams had one season with more than 30 homers or over 100 RBI.

Now, what about Fielder? Who resembles him most and would they have been worth an eight-year-plus contract? The names, please.

Eddie Murray would probably have been worth it. Mark Teixeira, undetermined. As for the rest, most were young stars who hit the career skids long before a Fielder-length contract could pan out: Juan Gonzalez, Jose Canseco, Greg Luzinski, Darryl Strawberry, Boog Powell, Jim Rice, Orlando Cepeda and Kent Hrbek.

One of these slugging giants will lead his team into the World Series. Feel free to join the fans of Milwaukee and St. Louis in a blend of jubilation and sadness at what may be the last glory days of a seminal franchise player.

Nobody is Ruth, but Pujols may be our best approximation of a hitter whose deeds we can barely believe. Fielder could end up a Hall of Famer. But remember the distorted value propositions of our baseball times.

Pujols and Fielder: Do you buy them, and risk buyer’s remorse for what seems like eternity. Or do you lose your one crazy chance to grab them — forever. It’s a narrow thing and fascinating. This is their stage, their hour. They’ll never be better. The question is: How long will they be this good?