The ATP World Tour is set to square off against one of its tournaments in a Delaware courtroom. All that’s at stake is the future of men’s tennis and the governance of all non-team sports. Barring a settlement, the antitrust case could determine just how far a rules-making body can go in setting tournament schedules, compelling players to compete in certain events, establishing a ranking system and awarding sanctions.

These functions are claimed not only by the ATP, which is being sued to undo a series of schedule changes, but also by other entities ranging from the PGA Tour to Olympic federations, according to a Sports Business Journal story.

The organizers of the Hamburg, Germany, tournament are suing the ATP, which is incorporated in Delaware, under U.S. antitrust laws for its decision to downgrade the tourney’s sanction. Hamburg’s demotion arrived as part of the ATP’s 2009 calendar plan, which aims to place top tournaments in strategic locales and compel top players to compete in the tour’s elite eight events. Hamburg is arguing that the ATP is a cartel that illegally manipulates event sanctions and controls player movements.

The trial will not affect team sports, which have U.S. antitrust law exemptions to varying degrees, but individual sports are another matter. The jury trial is scheduled to take two weeks. In pretrial papers, the court laid out 73 jury questions, underscoring the complexity of the case and the possible outcomes.

At its core, the Hamburg case is about whether the ATP functions as a league. If it is seen as such, then it likely will be afforded antitrust protections held by other sports leagues, which U.S. courts have ruled are allowed to collude to set schedules, pool TV rights and choose which teams are part of the league.

But if the ATP is viewed as less than that – say, for example, a disparate set of global tennis events unrelated to one another, no different than non-sports businesses that are not allowed to collude – then the court could tear apart the fabric of men’s tennis.

Hamburg’s tourney is claiming $76.6 million in damages. While observers are divided on whether the court could find the ATP in violation of antitrust laws, there’s even less certainty of what damages might be awarded.

Because Hamburg existed through this season as one of the top events, making it a party to the current system for many years, a damages amount is hard to fathom.