I see bee dee on BF reckons Polak is a done deal  ???.
As for Perry - he's 21 so I'm guessing the club thinks like many talls he has taken longer to develop and we can grab him off North just as he's about to break into the seniors after 4 years on their list. He played 8 games this year.  
----------------------------
Joel Perry   

Guernsey Number: 37
Height   192 cm
Weight:   95 kg
Recruited From:   Upper Ferntree Gully/Eastern U18
Debut:   2006
Date of Birth:   18 June 1985    
ABOUT
A tall utility, he played two pre-season competition matches in 2005, but failed to break into the Roos’ line-up over the premiership season and now has spent three years as a development player. However, the former Eastern Ranges junior was an emergency for one game, in round nine. 
PLAYER STATS
(as at the completion of the 2006 season)
Games: 8
Goals: 0
Brownlow Medal: career votes 0.
Player honours:
Draft history: 2002 National AFL Draft 3rd round selection (Kangaroos) No. 31 on-traded by St Kilda to Port Adelaide for Byron Pickett. 
AFL 2006 Premiership Season
Round      Date                    vs.             K     H     P     M   HO   T   FF   FA   G   B
Round 2   08/04/2006   Geelong            2     7      9      3      0      1      0      0       0      0
Round 3   17/04/2006   Collingwood   5   13   18   4   0   1   0   2   0   0
Round 4   23/04/2006   West Coast     6   4   10   2   0   0   1   1   0   0
Round 5   29/04/2006   Melbourne   7   4   11   7   0   1   0   0   0   0
Round 6   07/05/2006   Hawthorn   9   8   17   7   0   2   0   1   0   0
Round 7   14/05/2006   Adelaide     8     4    12     1     0     0        2    2    0    0
Round 8   20/05/2006   Fremantle   4   4   8   2   0   0   0   0   0   0
Round 15 15/07/2006   Brisbane    7   6   13   6   1   1   0   0   0   0
http://kangaroos.com.au/default.asp?pg=players&spg=playerprofile&personid=125268