As St. Louis fans try to ignore that slugger Albert Pujols may turn his back on the Cardinals and leave as a free agent at season’s end, the star goes hitless and grounds into three doubleplays in a 5-3 season-opening loss to San Diego. (Jeff Roberson/Associated Press)

ST. LOUIS — At the intersection of baseball’s greatest player, baseball’s greatest fan base and baseball’s greatest day, there was an awkwardness. It was opening day in St. Louis, where the fans all wear red and congregate outside Busch Stadium hours before first pitch, and where the organist plays “Here Comes the King” for 30 minutes straight while Stan Musial, Bob Gibson and the Budweiser Clydesdales parade past the stands.

But where did Albert Pujols fit into all this pageantry and celebration, this annual spring re-connection between the storied St. Louis Cardinals and their adoring, faithful followers?

On the one hand, it was permissible, on this of all days, to pretend nothing was amiss — that Pujols, the incomparable first baseman, would always and forever be a Cardinal, no matter what, and that the contract impasse that darkened the opening of the team’s spring training camp six weeks ago was so far from anyone’s minds as to be meaningless.

This, after all, is the approach maintained by the Cardinals themselves, with their manager, Tony La Russa, preaching tunnel vision, and Pujols himself, concerned about the potential distraction, willing neither to negotiate a new contract during the season nor even to discuss the situation publicly.

“The bottom line,” said Cardinals General Manager John Mozeliak, spouting the company line, “is that Albert is signed for 2011, and that’s how we’re going to approach it.”

But for the realists in the crowd of 46,368 on Thursday afternoon, who witnessed a 5-3 Cardinals loss to the San Diego Padres in 11 innings — in which the home team blew a one-run lead in the ninth and allowed the go-ahead run to score on an error — it was impossible to pretend all was right in the Cardinals’ universe.

“I think about it constantly — this could be [Pujols’s] last opening day” in St. Louis, said Matt Wright, a 26-year-old Cardinals fan from nearby St. Charles, Mo. “I want to go to as many games as I can this year, because this could be the end.”

Pujols — a three-time National League most valuable player and nine-time all-star who is now a little more than seven months from free agency — drew the afternoon’s loudest cheers during the pregame introductions, as expected. He is the most popular Cardinal since Musial, who might be the most popular sporting figure any town has ever known.

But when Pujols came to the plate in the bottom of the first, with a runner on third and one out — the appropriate spot for a sustained, roaring ovation that would force the great slugger to step back and doff his helmet in appreciation — it was something less than sustained, something less than roaring, and Pujols didn’t feel obliged to acknowledge it.

He dug in, crouched into his batter’s stance and popped up weakly for the second out, part of an ugly 0-for-5 day that saw him ground into a career-high three double plays. The last of those, with a runner on first and nobody out in the bottom of the 10th, drew a smattering of boos.

“This is about playing baseball right now,” Pujols said after the game, dismissing a question about the fans’ reaction, “not about what [happened with the contract talks] a month ago, or what the fans are saying.”

Booing Pujols might have been unthinkable as recently as six months ago. Was it simply the visceral reaction of a small segment of the crowd to his atrocious day at the plate, or were some Cardinals fans beginning the process of detaching themselves from their superstar?

“One player is not bigger than the team,” said Cardinals fan Tom Lomax of St. Louis before the game.

At this point, the Pujols/Cardinals standoff — with the best player in the game coming to the end of an eight-year, $114 million contract — is a news story without news. The sides cut off negotiations, at Pujols’s request, when they failed to reach an agreement before his Feb. 15 deadline.

“The one thing I can say,” Mozeliak said Thursday, “is that the relationship between Albert and the St. Louis Cardinals is still very positive, and one that both sides want to see work out long-term.”

Barring a change of heart, there will be no more substantive talks before the end of the season, at which point Pujols will be weeks from free agency.

“Cardinals fans will always respect Pujols, no matter what,” said Mike Sweeney, 25, of St. Charles, Mo. “We’re still going to cheer him. As long as he’s not with the Cubs.”

By the end of Thursday’s game, the stands were about a quarter full and the afternoon sun was gone. The Cardinals had lost. Pujols had accounted for a staggering eight outs. And the unthinkable — the possibility of St. Louis’s No. 5 wearing another uniform — had drawn one day closer.