When running back Christian McCaffrey surprisingly sat out of Monday night’s game against the Jets, my immediate thought was that it probably wasn’t a surprise for the 49ers.

After the 32-19 win over the Jets, McCaffrey’s replacement confirmed that.

Jordan Mason, who went undrafted in 2022, had 28 carries for 147 yards and a touchdown. He explained what happened during a postgame interview with ESPN’s Lisa Salters.

She asked Mason when he knew he would start.

“Maybe Friday, Friday night,” Mason said. “Something like that.”

But the 49ers didn’t label McCaffrey “questionable” until Saturday. If Mason knew he would start Friday, the 49ers knew it. And they used the injury reporting system to hide the truth for as long as possible.

That’s not a criticism of Mason. He was telling the truth. In doing so, he exposed the inherent flaw in a set of rules that allow a team to label a player “questionable” even when there is no real internal doubt about his status.

On the one hand, it is permitted by the broad process for disclosing injuries and player status. On the other hand, it underscores the existence — and value — of insider information.

The 49ers (as evidenced by what Mason said) knew the truth. No one else, presumably. In a world without legalized gambling and fantasy football, there’s an all-fair dynamic that applies. But now that money is changing hands based on decisions made with information the team has provided, it’s a problem.

Should McCaffrey have been listed as questionable? Absolutely, at the very least. There is also an argument to be made that he should have been ruled out.

In fact, if the 49ers were playing in New York tonight, he likely would have been downgraded to the out, as he likely would not have made the cross-country flight due to his calf/Achilles injury.

As far as anyone knows, the 49ers have known for a few days that McCaffrey would be out. The biggest clue came on the initial injury report last week, when his calf injury suddenly became an Achilles indication as well.

And while the 49ers may have violated the spirit or even the letter of the rules, the rules are so loose and incomplete that teams can take subtle liberties.

The 49ers just wanted to win. Keeping the Jets guessing as long as possible helped them strategically. But it also affected the betting (particularly prop bets) that was placed prior to the game.

By keeping the information secret until it was time to declare the inactive players, it worked. No one knew McCaffrey wasn’t playing.

Except for Mason. And probably the coaching staff.

That said, the 49ers will surely go into aisle five cleanup mode, claiming that Mason misspoke or something. Either way, it’s clear that tonight’s development wasn’t nearly as stunning for the 49ers as it was for the rest of the world.

If the NFL continues to line its pockets with gambling money (which means team owners are also allowed to own up to five percent of the companies that operate sportsbooks), then the NFL is obligated to come up with a more transparent and accurate way to level the playing field for people who legally wager money based on incomplete information.

Especially when those who knew the truth were in a position to take full advantage of it, if only by sharing that information with people who could invest their money where their insider information resides.