Increasing designated player slots in mls

[jordymakin]

Hi im playing as Vancouver in the mls and have 2 designated player slots, can I increase it? I've read on wikipedia that some clubs have paid for an extra slot. Round about $250,000. I have jermaine jenas and owen hargreaves as my current 2 players but other clubs have a third. I wondered if you could buy another one in the game.