Dave Gettleman developed a “thick rhino hide” during the onslaught of criticism over his Leonard Williams trade.

Now, Gettleman has an unexpected chance to show he has the boldness of a lion and the cunning of a fox — and change the narrative around himself and the Giants.

All the general manager has to do to stop the denunciations is swap in Williams for Jadeveon Clowney.

That might be the craziest thing you read today — straight from a video game or fantasy football league — but it’s simpler and more sensible than it seems.

In three steps: 1. Find out Clowney’s can’t-refuse number on a one-year contract. 2. Rescind the franchise tag on Williams. 3. Free up an additional few million in salary cap space by restructuring bonus figures on another contract.

“I don’t think it’s crazy,” NFL Network analyst Brian Baldinger said when the scenario was posed to him. “The guy that has to suffer is Gettleman, but nobody thought Clowney would still be here. It’s, ‘I like the blue coat [of paint], but the red Ferrari is really what I always wanted.’ ”

The more detailed version goes like this: The Giants placed a franchise tag on Williams, reserving $16.1 million for a one-year contract. Williams has not signed the tender and could follow the path of tagged players who hold out to build negotiation leverage without incurring fines.

The two sides have until July 15 to reach a long-term extension, at which point it is tag or bust. The salary becomes guaranteed the moment Williams signs. The Giants can rescind the offer without penalty until he does — a rare move unpopular in locker rooms, but one which Gettleman prudently pulled on Josh Norman while with the Panthers.

Sources told The Post the Giants have expressed interest in Clowney, who started off asking for $20 million per year on a multi-year contract, but has found a surprisingly depressed market five days into free agency. He reportedly is open to a high-paying short-term deal with a chance to reenter free agency when the salary cap skyrockets next season.

The Giants should strike, substituting the allure of New York City for the chance to win a Super Bowl in 2020.

When the Giants traded two draft picks to the Jets in October for Williams, then a pending free agent, Gettleman was overconfident he would finalize a multi-year extension. If Williams is not going to take a hometown discount — the tag salary often is used as the baseline for average annual salary on an extension, but the Giants are hoping to knock about $4 million off that number — then it is an apples-to-apples comparison.

One-year deals for both players, so who makes the team better: Williams or Clowney? No prolonged salary cap ramifications and a bone tossed to a fan base disheartened by the NFL’s worst three-year record.

With Markus Golden unsigned in free agency, the Giants do not have a player who had more than 4.5 sacks, seven tackles for loss or 13 quarterback hits last season. Newly signed Kyler Fackrell is the only player with more than five sacks in any year of his career.

The Giants invested three high draft picks on defensive tackles (Dexter Lawrence, B.J. Hill and Dalvin Tomlinson) who lost snaps after Williams was acquired. Clowney comes off the edge, where need and impact are greater.

The knocks on Clowney don’t apply here: Injury-prone? It’s a one-year deal on a team with minimal playoff expectations. Unmotivated? He will be playing for his next contract in a market in which effort is scrutinized. Not enough big plays? Williams had a half-sack and two tackles for loss last season.

The Giants wouldn’t risk losing Williams for nothing, either. Negotiate with Clowney and only rescind the tag if and when an agreement is in place.

“Jadeveon is a guy that needs structure,” Baldinger said, “but he is the much more disruptive player and is capable of taking over games. You get the better player in the short-term, and it addresses a bigger need.”

The best way to flip the script on the Williams trade and move past the wasted draft picks? Swap him for Clowney.

It really is that simple.