free up cap space

In sports management, to increase the amount of money that a professional team has available to spend on players' salaries, such as by trading or releasing players. (A salary cap is a limit on the total amount of money that a team can spend on players' salaries.) The team released a few players to free up enough cap space to sign its star center. I think this trade was just a salary dump. I bet they're trying to free up cap space for some big free agent signing. How exactly are they going to free up cap space when they have so much money tied up in their star players?