Now it starts to gets interesting. Now Major League Soccer must weigh the advantages of its closed-end business model against the opportunity for owners to share in a $4 billion windfall.

They must weigh whether American soccer should adopt a structure similar to those in place almost everywhere else; whether second- and third-tier teams should be afforded a chance to move up in class.

Change is not imminent, but it no longer appears impossible.

A Sports Business Journal report that the MLS has rejected a 10-year, $4 billion media rights deal contingent on the promotion/relegation model standard in European leagues can be read as a reaffirmation of the MLS’ guiding principles. But it might also be the first step in a big-money mating dance bound to be revisited as current contracts expire.

Either way, it stokes the ongoing debate over promotion and relegation – the performance-based process by which teams can rise or fall between leagues of different levels – emboldening America’s many Eurocentric soccer fans to envision some tantalizing and newly plausible scenarios.

Consider: The United Soccer League’s Louisville City FC did not submit an application for MLS expansion by the league’s Jan. 31 deadline. Even if the team’s owners were equipped to pay the $150 million expansion fee, their failure to apply leaves Louisville ineligible for either of the next two rounds of expansion. As a result, LouCity's push for city financing of a new stadium, pitched as a step toward MLS status, invites skepticism and deserves scrutiny.

Yet if MLS owners can be sold on cashing in on the concept being floated by MP & Silva’s Riccardo Silva (co-owner of the North American Soccer League’s Miami FC), Louisville’s prospects could be enhanced considerably. Were promotion and relegation already in place, and the top three USL teams were eligible for advancement, the home team would have moved up after each of its first two seasons.

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It wouldn't be that simple, of course, not with so much money at stake. But a noisy and persistent portion of soccer's U.S. constituency argues that promotion/relegation is the path to greater prosperity for American professional leagues and would likely lead to improved showings in international competition.

When that lobby is backed by billions, it becomes mighty difficult to ignore.

“There are definitely people here who would like to see it,” Louisville City spokesman Jonathan Lintner said. “It’s very much a live debate, no matter how realistic it is.”

To date, the biggest barrier to promotion and relegation in the American soccer pyramid has been the risk appetite of MLS owners. With expansion fees now set at $150 million, that over and above the costs of operating a franchise, the prospect of being demoted to a lower league creates a level of uncertainty and potential losses sure to shake the confidence of prudent investors.

It’s easy to sneer at those concerns, as a Deadspin columnist did Monday in referring to the MLS as “the famously cowardly league,” but rants along those lines serve mainly to remind readers of the rarity of a sportswriter with an MBA. Though it’s always fun to spend other people’s money as if it were inexhaustible, this is not the most persuasive form of punditry.

If the MLS is ever to embrace promotion and relegation, it will be because a convincing case can be made based on dollars and cents and not because increased mobility between leagues might appeal to spectators weaned on the Bundesliga or the English Premier League.

For the moment, Silva’s proposal can probably be classified as a stunt. MLS broadcast contracts run through 2022, and current rightsholders (ESPN, Fox and Univision) retain exclusive negotiating windows to extend those deals. Still, if Silva is sincere – and MP & Silva has been a serious player in soccer, tennis and motor sports – MLS owners will surely want to hear him out when negotiations reopen, if only to raise the bidding by their existing partners.

According to reports, Silva’s offer is worth roughly four times what the MLS currently reaps for its broadcast rights. If his promotion/relegation requirement makes MLS owners queasy, a reliable, multibillion-dollar revenue stream has a way of overcoming objections.

Tim Sullivan can be reached at (502) 582-4650, tsullivan@courier-journal.com or @TimSullivan714 on Twitter.