Could Kyrie Irving, left, and Kevin Durant bypass Madison Square Garden for Barclays Center? (Ethan Miller/Getty Images)

The NBA’s free agency period was already shaping up to be a doozy, with several top-tier stars likely available and big-market teams waiting to throw gobs of cash at them. With a reported trade Thursday, the Brooklyn Nets threw their hat into the ring — and may have thrown New York Knicks fans into a state of panic.

As first reported by ESPN, the Nets are sending shooting guard Allen Crabbe, the No. 17 pick in this year’s draft and a protected first-rounder next year to the Atlanta Hawks for small forward Taurean Prince and a 2021 second-round pick.

Dumping the contract of Crabbe, who is set to earn $18.5 million next season, gives Brooklyn $46 million in salary-cap space this summer. If the team lets restricted free agent guard D’Angelo Russell sign elsewhere, it could clear enough room to sign two maximum-level free agents.

The Nets have already been linked to all-star point guard Kyrie Irving, who is widely expected to opt out of his contract with the Boston Celtics and test the market. In turn, Irving has been linked to another impending free agent, Golden State Warriors forward Kevin Durant, and Brooklyn might be able to reel them both in.

Which brings us to the Knicks, who have been presumed to be eyeing a Durant-Irving tandem as their Plan A since February. That was when they went all-in on free agency by clearing acres of cap space in a trade that sent star forward Kristaps Porzingis to the Dallas Mavericks.

Now the Knicks could be looking at a scenario in which their coveted pair of superstars do indeed take their talents to the Big Apple, but wind up bypassing Madison Square Garden for Barclays Center.

That thought is more than enough to give Knicks fans agita.

Their team can point to its famous arena, a far larger fan base in the city and the glory that would accrue from bringing one of the league’s marquee franchises its first championship in almost five decades. New York also has the third pick in the upcoming draft, which it can use on a highly regarded prospect such as Duke’s RJ Barrett or possibly package in a trade for a huge name such as the New Orleans Pelicans’ Anthony Davis.

The Nets can counter with a better-looking supporting cast — Brooklyn won 42 games and made the playoffs while the Knicks won 17 and had the NBA’s worst record — and less pressure while still enjoying all that New York has to offer. Oh, and the Nets could also mention that their owner is not James Dolan (for the record, it’s effectively Joseph Tsai, a billionaire businessman who holds a 49 percent share but is expected to exercise his option to purchase Mikhail Prokhorov’s majority stake in January 2021).

There’s no guarantee that Durant or Irving will join either team. In Durant’s case, he may well choose to stick with the Warriors and while it would be something of a shock at this point if Irving re-upped with the Celtics, there are other squads with cap space to spare.

In an intriguing bit of symmetry, the two teams in the West Coast’s biggest city are also positioned be also be major players in free agency. The Los Angeles Lakers have room for one max contract and they already have LeBron James, although the appeal of playing with him may not be what it once was. Thanks to some luck in the NBA draft lottery, they also have the No. 4 overall pick to possibly use in a trade, with Davis again looming large.

The Los Angeles Clippers can sign two max free agents and recently submitted a surprisingly feisty playoff performance against the Warriors. Kawhi Leonard, a Southern California native who can walk away from the Toronto Raptors this summer if he so desires, might be a perfect fit for the Clippers, and there has been some speculation that Irving could be interested in joining James, his former title-winning Cleveland Cavaliers teammate, on the Lakers.

Other prominent players expected to be available when free agency officially starts at 6 p.m. June 30 (contracts cannot be signed, however, until noon on July 6), include Golden State’s Klay Thompson, the Charlotte Hornets’ Kemba Walker and the Philadelphia 76ers’ Jimmy Butler and Tobias Harris.

If the Nets lose out on Irving, they could potentially have a solid fallback option in retaining Russell, a similarly offensive-minded point guard who became an all-star last season. Brooklyn also still has the 27th and 31st picks in this year’s draft.

The Hawks, meanwhile, have accumulated a massive amount of capital in the draft, with the eighth, 10th, 17th, 35th, 41st and 44th picks. ESPN, citing a source, reported that the future first-rounder from the Nets is protected if it falls in the lottery (one through 14) for each of the next three years, after which it would convert into two second-round picks.

Atlanta could use some of its picks to possibly move up in the draft or in a trade for other assets. In any event, the team appears well-positioned to add to a promising young core that features Trae Young, John Collins and Kevin Huerter.

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