According to Enigma in the impressions thread, it sounds like you can only play 2vs2. Here's what he said about it:
Co-op can not be played in franchise mode this year. (they tried but it will be next year)
It can only be played in exhibition and online.
Only two PS3s can do co-op online with the current network. Meaning...
If you and a friend are on one PS3 in the same room, you can play against either the CPU online, two other people on the same console somewhere else online, or against one person online.
You and a friend on another PS3 somewhere else can play co-op versus the CPU online as well.
(2vs2)
(2vs1)
(2vsCPU)
Local you can have 4 people on one console (2vs2), (2vs1) and (2vsCPU).