The only problem with that, is that in Madden he would take up a roster spot which he doesn't right now in real life. Yeah they'll pay him, but they won't have to count him as a member of the 53 man roster. You have to do that in Madden. So what's more realistic... Having a guy on the team who won't be welcomed back and won't be able to play till 2010 at the earliest... thus keeping someone off the 53 man roster that would actually be able to play, but now can't because you don't have enough roster space. Or is it better to just drop him to 0 and release him? Considering Madden doesn't have accurate rosters to begin with, I'd say cutting him is the best, because lets face it... you keep him on and get the roster to 53 men, (or is it 55) then you can't sign, say another quarterback to replace Vick, and you can't sign another one to replace Shockley. Now that's not realistic.
But lets face it, nothing we come up with is going to be completely realistic, but I say cutting him off, while giving salary cap space, will give you the full roster.
EDIT: Sorry if this reads like a 2 year old wrote it... I haven't had much sleep in the past three days.