Until now, the most famous bet in football history was Carroll Rosenbloom’s under-the-table $25,000 wager on his Baltimore Colts winning the 1958 championship game.

Such a number looks like small potatoes now as the National Football League opens its 100th season this week with a full, arms-open-wide embrace of gambling This time, it’s legal, though – and this time, the bets will be computed in the millions.

All Rosenbloom’s bet might have done is change the course of pro football history.

He owned the Colts back in the 1950s, back when they played the New York Giants in the fabled Sudden Death championship contest that’s still called “the Greatest Game Ever Played” because it changed America’s sporting culture.

Back then, baseball was the national pastime. The Sudden Death game was the start of pro football’s sporting dominance, which enters fertile new (but tricky) territory now with the widening legalization of sports betting across the country.

Last year, the U.S. Supreme Court struck down a law that had banned sports betting in most states. A dozen states have formally legalized it. Several more are close. Maryland legislators will likely take a look at it this coming General Assembly session.

Not that legalisms have ever stopped fans from betting.

Pro football’s always drawn huge numbers of bettors. Fans study the weekly point spreads like haftorah lessons. As the league commences its 100th season, any honest reading of its history acknowledges that some of its earliest owners were themselves hip deep in gambling.

The Giants’ owner Tim Mara had been a bookmaker at Saratoga Racetrack. The Steelers’ Art Rooney owned a racetrack, and the Chicago Cardinals’ Charles Bidwill made his fortune printing pari-mutuel tickets.

And then there was Rosenbloom. Everybody, including then-NFL Commissioner Bert Bell, knew Rosenbloom was betting every week. The league’s position on all betting was: Pretend it isn’t happening. Make sure nothing happens that effects play on the field. And to those such as Rosenbloom, please be discreet.

Rosenbloom used to place his wagers with an eastside bookmaker named Gussie Huditean, who owned a Highlandtown nightspot known as Gussie’s Downbeat. Long after Rosenbloom died in 1979 – under questionable circumstances, while Rosenbloom was swimming – Gussie insisted the Colts’ owner bet with him every week.

But on the championship game, Gussie said, Rosenbloom handed over $25,000.

The bet set up one of the most whispered-about plays in NFL history. The point spread on the title game had the Colts winning by 3½ points. In the overtime period, they drove deep into Giants’ territory, where an easy field goal would break the 17-17 tie.

To many, it seemed far safer than going for a touchdown. But a field goal would only give the Colts a three-point victory – a championship, yes, but it wouldn’t have covered the point spread, and would have left Rosenbloom $25,000 poorer.

Is that why the Colts went for the touchdown?

Rosenbloom wouldn’t say. He wouldn’t even admit he’d placed a bet. Coach Weeb Ewbank simply said he trusted quarterback John Unitas more than he trusted the erratic kicker Steve Myhra.

Over the years, if you asked any of the Colts about it, they were insulted. That game was the triumph of their lives, and they resented anyone implying Rosenbloom’s money was even a minor factor in their victory.

But the legend hung over the sport for years. It became a reference point when frustrated gamblers saw one of their bets slip from victory to loss over some inexplicable play, or some questionable call by a referee.

And that leaves the league in its newest, trickiest territory. If legalized betting expands the dollars, does it also expand the accusations about gambling money affecting the games themselves?

There’s more money coming in – but is the league opening a door and stumbling off a cliff on the other side?

A former Baltimore Sun columnist and WJZ-TV commentator, Michael Olesker is the author of six books, most recently “Front Stoops in the Fifties: Baltimore Legends Come of Age” (Johns Hopkins University Press).