A few reasons:
1) Because he is not a chior boy. (Has been charged with physically abusing several women while in Denver and Miami)
2) I cant see him playing nice with 89 and Marty/JR knew it wouldnt work.
3) Marty's refusal to give up multiple valued draft pics for proven players. (Eventhough he couldnt draft for poo and would trade them for projects in the draft.)
4) His hands had become questionable while in Miami
5) And he can be a headcase... (I personally think his admission to having a personality disorder is BS, but thats just my honest opinion.)
Obviously im just guessing here...
7-1 with the bears. Thats all i need to know.