If you think Tom Brady controlled the NFL for the last two decades, you have not seen anything yet.

There never has been a more high-profile free agent than the six-time Super Bowl champion, who will hit the open market for the first time in his career when the legal tampering period for negotiations opens at noon Monday.

Maybe Brady, 42, agrees to return to the Patriots. Maybe he elevates a contender like the Cowboys or 49ers. Maybe he brings his star to a celebrity hotbed like Los Angeles, Las Vegas or Miami.

Maybe he agrees to terms one minute into the window. Maybe he will wait a day … or two … or three. Wednesday is the first time free agents officially can sign with new teams.

Multiple reports say Brady is operating as if he is changing teams.

Brady can hold the rest of the NFL hostage because any team that feels it has a chance of adding the Greatest of All Time can’t get into a salary-cap or depth-chart bind by first signing Philip Rivers, Teddy Bridgewater or Jameis Winston.

Unless Brady is a close friend and offers you the courtesy of a heads-up, as could have happened for Titans coach Mike Vrabel before they moved ahead Sunday on a reported four-year, $118 million extension for Ryan Tannehill.

Even without Tannehill, there is unprecedented depth on the quarterback market, but Brady is the domino causing the rest of the NFL to pause. And if you don’t think Brady is enjoying every second of the attention then you didn’t see his Super Bowl commercial and the mysterious Twitter teaser that preceded it.

Brady’s Super Bowl nemesis, Eli Manning, retired earlier this offseason rather than test free agency for the first time after 16 seasons with the Giants. But Brady is the ageless wonder.

Some NFL personnel scoff at the suggestion Brady ever would leave the Patriots. Others point to Brady’s not-so-hidden displeasure at the receiving corps assembled last season after Rob Gronkowski’s retirement.

Brady wants to be courted. Years of taking less money than other top quarterbacks to help the Patriots build a winner will do that to an ego. So will hearing about how coach Bill Belichick was prepared to go with quarterbacks Jimmy Garoppolo or Jacoby Brissett if Brady retired years ago.

Breaking up a dynasty is a risk to Brady’s legacy, especially if Belichick keeps winning. On the other hand, capturing a championship with a second team is something not even Michael Jordan or Joe Montana accomplished.

The silence regarding negotiations between Brady and the Patriots could be a prelude to parting ways. He looked painfully awkward — no easy task with his Hollywood looks — when seated next to Patriots receiver Julian Edelman at a basketball game as Edelman told cameras his quarterback is “coming back.”

Or it just could be the CIA-like code of silence for doing business in New England. Maybe only Brady, agent Don Yee, Belichick and Patriots owner Robert Kraft — the man whose fondness for Brady and checkbook could render moot all this discussion — know the answer.

Even the teams not in the Brady sweepstakes are paying close attention.

Imagine the Jets, Bills and Dolphins — who watched the Patriots win 16 of the last 17 AFC East titles — finally feeling like there is a path to a playoff home game. Facing the Bridgewater-led Patriots twice per year isn’t quite so intimidating, no matter the aura of Belichickian genius.

Or the Chiefs and Ravens exhaling because the AFC playoffs don’t run through Foxborough.

Or, on the flip side, NFC powers whose path to the Super Bowl becomes more difficult if Brady winds up changing conferences.

Whatever happens, whenever it happens, wherever it happens, the entire landscape of the NFL in 2020 is waiting.