On the madden PS3 forums on operation sports they have a madden hex editing, it also works for the NCAA game too (I believe). Part of the madden roster editing is decrypting/encrypting the data, is this the same PS3 encryption that's used for the 2K games? If so it's easy/simple to do.
The tool is "Bruteforce Save Data"
http://www.operationsports.com/forums/m ... r-ps3.html
Follow the links in the first post
http://www.operationsports.com/forums/n ... r-ps3.html
^the bruteforce save data tool is here
Sorry if this has been posted before and it doesn't work. I am just assuming it might be the same encryption, and would allow editing of the 2K ps3 rosters.