Recent comments from NBA commissioner Adam Silver about tweaking the league's playoff format drew intense media coverage, but sources say there is also some behind-the-scenes momentum for the idea of a play-in tournament determining the last two seeds in each conference -- to the point that two specific proposals are circulating at the highest levels within teams and the league office.

The play-in proposal that has generated the most discussion, according to several sources: two four-team tournaments featuring the seventh, eighth, ninth, and 10th seeds in each conference. The seventh seed would host the eighth seed, with the winner of that single game nabbing the seventh spot, sources say. Meanwhile, the ninth seed would host the 10th seed, with the winner of that game facing the loser of the 7-versus-8 matchup for the final playoff spot.

The implementation of a play-in tournament is not imminent. It falls behind the one-and-done rule and perhaps reseeding the playoffs 1-16 regardless of conference in the current reform pecking order. (It could go hand-in-hand with that change, only with one play-in tournament instead of separate brackets for each conference.)

It is not coming next season, and it would be a shock if the NBA adopted it in time for 2020 or even 2021. It may never happen. Any such change would need approval from the competition committee, and then from a supermajority of 23 NBA teams. That process has not even started.

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A play-in would require collective bargaining with the players' union. There is also debate within the league about whether a play-in would inspire as much fan interest and hype as supporters hope. After all, we are talking mostly about .500-ish teams battling for the right to get destroyed by top seeds. In theory, revenue from a play-in tournament -- or a midseason tournament -- could ease the league toward slashing a few games from the 82-game schedule, but it is unclear any such tournament would rake in sufficient cash.

But the fact the discussion around the league has crystallized around one or two proposals indicates that a play-in tournament is no longer some pie-in-the-sky idea. It fits within the NBA's broader goals of reducing the incentive for teams to tank, and maintaining peak fan interest across the full NBA calendar.

Backers of the play-in tournament view the 7-through-10 proposal as a workable compromise. Three years ago, when the league first started seriously discussing the concept, supporters initially pitched a single-elimination, four-team tournament for the eighth playoff seed involving the teams that finished eighth, ninth, 10th, and 11th in each conference, sources have said.

Opponents recoiled at including the 11th seed, arguing that doing so would reward awful teams and devalue the regular season, sources have said. It's possible that the promise of a tournament appearance might motivate teams so that the average 11th seed would be a little better than it is today, but the debate for now has settled on drawing the line at the 10th seed.

The proposal gives the seventh and eighth seeds an edge over teams that finish ninth and 10th -- a method of making sure regular-season success means something in the play-in tournament. Teams that finish seventh and eighth get two chances to win one game to clinch a playoff spot, including a guaranteed win-and-get-in home game for each. The ninth and 10th teams need to win two games without a loss, and the 10th seed would need to win two consecutive road games.

Other top executives, including at least one prominent general manager, have pushed a simpler, shorter alternative: No. 7 hosts No. 10 in a winner-take-all for the No. 7 seed, and No. 8 hosts No. 9 in a winner-take-all for the No. 8 seed, per league sources. That approach appears too radical to gain widespread approval.

A play-in tournament would complicate the lottery system. If a team finishes 10th but then wins the No. 8 seed in the play-in tournament, do they stay in the lottery or effectively swap places in the draft order -- with a team sporting a better record replacing them in the lottery? Or should the league reserve the lottery for the 14 teams with the worst regular-season records, regardless of the outcome of any play-in tournament?

Some team higher-ups have pitched the idea of including the seventh and eighth seeds in the lottery -- expanding the lottery field from 14 teams to 18, sources said. That would guard against the possibility of any team tanking its way out of the tournament.

And that is the broader hope behind any play-in proposal: that more teams toward the bottom of the standings would try until the end. It also would deter some selective tanking for playoff positioning above the play-in level; no team would tank from sixth to seventh to lock in a more favorable playoff matchup if doing so slotted them into a high-variance tournament. Even tanking from fifth to sixth could be risky until the very last day of the season if the standings are close enough.

Backers also envision the tournament as a way of sparking interest during what can be a dead period of the NBA season -- March and April. It wouldn't work every season. Right now, the West has eight contenders -- from the Spurs at No. 3 to Utah at No. 10 -- for six playoff spots behind Golden State and Houston. Under a tournament setup, all those teams would be guaranteed at least a win-or-go-home shot at making the real postseason. Without a legitimate No. 11 team pushing Utah, the current format might create more night-to-night drama in the West.

But there will be seasons when the possibility of the No. 11 or 12 team butting into the play-in would create drama down the stretch. And even today, the tournament would manufacture another race to win the No. 6 seed -- and stay above the tournament.

On the flip side, in the East, we could be one Pistons slump (and Detroit's schedule is gnarly) from having the eight playoff teams set in stone early. A play-in would keep the new Blake Griffin Pistons alive, and give a semi-dangerous Charlotte team hope. The Hornets have underperformed their point differential, and they have real talent across the roster. What if their horrible luck in close games reversed itself at the right time?

There is no perfect solution to any of this. The only way to eradicate tanking is a complete overhaul of how NBA teams acquire talent, and no one has the stomach for that. A play-in tournament -- and this proposed play-in tournament specifically -- is worth discussing, and that discussion will probably intensify over the next few years.