I think this AFL article sums up why perfectly:
Defensive pressure in the forward line has been a hallmark of Fremantle's season, with unheralded Matt de Boer making the role his own in the past month. De Boer has shut down the opposition's chief rebounder in recent weeks, with Shannon Hurn (15 possessions) and Heath Shaw (14) notable scalps. He also put the clamps on Richmond's Brett Deledio in round five. Michael Johnson has emerged as a key to Fremantle's structure, with the forward giving Aaron Sandilands ruck support and allowing Mark Harvey to play an extra midfielder. Sandilands has been targeted in the middle of the ground as an escape option at kick-ins, with the 211cm giant punching the ball forward for his midfielders to run onto
Article Link http://www.afl.com.au/news/newsarticle/tabid/208/newsid/94610/default.aspx
Defensive pressure in the forward line has been a hallmark of Fremantle's season, with unheralded Matt de Boer making the role his own in the past month. De Boer has shut down the opposition's chief rebounder in recent weeks, with Shannon Hurn (15 possessions) and Heath Shaw (14) notable scalps. He also put the clamps on Richmond's Brett Deledio in round five. Michael Johnson has emerged as a key to Fremantle's structure, with the forward giving Aaron Sandilands ruck support and allowing Mark Harvey to play an extra midfielder. Sandilands has been targeted in the middle of the ground as an escape option at kick-ins, with the 211cm giant punching the ball forward for his midfielders to run onto
Article Link http://www.afl.com.au/news/newsarticle/tabid/208/newsid/94610/default.aspx





