Following the opening salvos in collective bargaining between Major League Baseball and the MLB Players Association, one thing is clear: The gap between the sides is not just enormous. It's fundamental.

MLB proposed a salary-cap system Thursday, marking the league's first foray into overhauling the sport's economic structure in more than three decades. The long-awaited proposal would set a hard cap of $245.3 million and hard floor of $171.2 million, aiming to shrink the disparity among team payrolls by a significant amount. The league's proposal -- which also called for a 50/50 revenue split and the centralization of all television revenue -- came one day after the MLBPA made a wide-ranging opening offer that called for a soft floor, new definitions of revenue sharing and pay increases for younger players.

The differences between the two show why those around the sport expect a protracted fight leading up to the Dec. 1 expiration of the CBA.…