SAN ANTONIO — As of Thursday, free agents signed last offseason can now be dealt, making this the unofficial start to NBA trade season.

For fans with keen interest in their club’s maneuverings, this is — with all due apologies to holiday revelers and, of course, the late Andy Williams — the most wonderful time of the year.

Teams have been allowed to make deals all season, but now several degrees of heat are added to the rumors. The possibilities multiply. It will all culminate with the NBA’s trade deadline February 23rd, and from now until then, interested parties will be sifting through potential moves both real and imagined.

Danny Ainge acknowledged Wednesday that the playing field will change now, but he’s not planning to attach himself to his phone the same way he will two months hence.

“It’s just a date that, with most rosters, everybody can be traded, so it makes trading easier,” the Celtics’ president of basketball operations told the Herald. “It’s not any magical date.

“I mean, you still have the trade deadline as the more magical time, and very few people are ready to make trades this early. It’s just a date that certain players that were signed in the offseason can be traded, so there’s more players per roster that can be used to make money work in transactions.”

For the Celts, Gerald Green can now be moved, but in that he’d played in just 12 of the 24 games entering Wednesday night, getting 120 minutes and 43 points, it is not expected that he will be a hot commodity.

More players will be free to be dealt on January 15th, when free agents who stayed with the same club can be placed in the window. Tyler Zeller fits this category for the C’s.

What could make this year’s trading period a bit different than in some previous seasons is that the price of talent underwent a major change last summer when the new television contracts were factored into the salary cap. Suddenly, big money was being thrown around, and free agents cashed in.

It’s always the case that this far into the season teams have a better idea of what they are and what they are not, which can affect them being buyers or sellers in the marketplace.

But the more interesting question becomes whether more players who are approaching freedom this year and, to some extent, even next will be made available by clubs that are not willing to pay them what someone else will. Clubs would prefer to get something in return for a guy who could just walk.

Doing the spreadsheets on future roster financials has always been a key for organizations, and it’s only increased in importance with the wave of NBA prosperity that has non-superstars breaking the bank.

In this scenario, the Celtics are at least poised with assets to make deals work, but that doesn’t guarantee the kind of opportunities they are seeking. It doesn’t mean the players they want will be up for bid.

“I don’t know,” said Ainge. “Listen, every team is different. I don’t think that there’s like a philosophy that is standard amongst every NBA organization.

“I think there’s some contracts that everybody thinks are good, contracts that people think are bad. I mean, every team has their own evaluation of players and own way to disperse the funds and use the cap in building a team.

“We all know what everyone’s making around the league. We all know that there’s more money available this offseason, too, even though there may be fewer teams with the amount of money that was available last year. There’s still a lot of teams with a lot of money to spend.”

The Celtics have money and players and draft picks to spend, which will make them among the more active trade season participants. But it’s most likely we won’t know until February how wonderful — if at all — it becomes for them.