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. 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.