(FORTUNE Magazine) – Put yourself in the cleats of the professional athlete. Having aced your way through an MBA in high finance, you are drafted in the second round by Green Bay Securities -- a well-established, medium-size Wisconsin brokerage far, far away (in every way) from your first choice on Wall Street. You could sit on the sidelines for a couple of years and sell your services to bidders of your choosing. But then you might miss the final leg of a bull market. So you sign with Green Bay and hope. Maybe someday your owner will trade you to Salomon Brothers. As every sports fan knows, owners of pro teams have traditionally exerted such control over their players. But why should they get away with behavior that would bring other businesses a summons from the trustbusters? Along with most economists, Beverley Pooley, an expert in sports law at the University of Michigan, argues that they should not: ''The owners' behavior would not be tolerated in any other walk of life.'' The owners have kept players in bondage without fear of violating antitrust laws for one reason: The players accepted restrictive employment conditions in return for higher salaries, better pension packages, and other benefits. As long as both sides agree to the rules in a collective bargaining pact, antitrust laws permit many labor practices that stifle competition. But now the players -- some 2,900 strong -- in all three big-money team sports are demanding to be set free. Football and basketball players are bargaining for broader rights to sell themselves as ''free agents'' to the highest bidder once their contracts expire. Argues Larry Fleisher, general counsel of the union that represents professional basketball players: ''Pro athletes are no different from the actor who gets $6 million for a picture, or the corporate CEO, or the guys at investment banks who are making the big dollars.'' Under current football rules, a free agent can change teams only if his new owner compensates his old owner. The required compensation has been set so steep that only one player has ever switched (defensive cornerback Norm Thompson moved from the St. Louis Cardinals to the Baltimore Colts in 1977). By comparison, baseball players have had fairly liberal free-agent rules since 1976, but an arbitrator ruled last month that the owners had conspired to frustrate the process by agreeing not to bid competitively against one another. Team owners have long put forth two arguments against free agency. First, they contend that bidding wars would raise salaries so high that some teams would collapse. ''Team owners are basically motivated by the glory that comes with winning,'' says Jerry Reinsdorf, a principal owner of both the Chicago White Sox baseball club and the Chicago Bulls basketball franchise. ''They would rather win games than make money. And when left to their own devices, they will go out and spend recklessly.'' Free agency must be restricted, Reinsdorf says, to protect the owners from themselves. Second, the owners maintain that the big-city teams in lucrative TV markets with abundant endorsement opportunities would use their money to sign all the best quarterbacks, point guards, sluggers, and pitchers. The richest teams would so dominate the competition that the fans would lose interest. Economists dismiss the owners' arguments. Says Robert McCormick of Clemson University, who has studied sports cartels: ''It's unfathomable that owners would systematically bid up salaries to the point where they drive themselves out of business.'' There's no broad public purpose to be served in protecting owners from their egos -- and certainly not at the expense of the players. From time to time, as in other industries, some owners will doubtless spend themselves into bankruptcy. But even owners who want to prevail at all costs know that bankrupt teams rarely make it to the winner's circle. Neither would free agency upset the competitive balance. Owners have always been able to trade players, and the athletes, like other commodities, generally wind up with the people who most need them. None of this will change under liberalized free agency. The economists aren't merely theorizing. Before the baseball owners entered into their conspiracy, they bid aggressively for free agents. Players changed teams frequently and salaries rose sharply. But no team went broke, nor was the relative parity among teams affected. Indeed, competition in baseball has arguably never been as balanced: Since free agency made its debut 11 years ago, ten different teams have won the World Series. While it may seem hard to believe, owners actually have a vested interest in maintaining strong rivals. IBM's shareholders will get rich if Big Blue dominates its competitors, but the owner of a sports team is best served by opponents who force games into extra innings, overtimes, and sudden-death play-offs. As Walter C. Neale, a University of Tennessee economist, once wrote about the great boxer Joe Louis: ''He wants to . . . maximize his profits. What does he need in order to do so?'' Neale's answer: ''A contender, and the stronger the contender the larger the profits from fighting him.'' Just ask Sugar Ray Leonard and Marvelous Marvin Hagler, whose championship fight last spring brought them at least $25 million.