So what impact will it have on his situation if JZ is added to the 40 man roster say next May or June?
If he comes up for the season in June, he does not use an option.
Additionally, from a bookkeeping POV, he does not accrue the 30 something days of service time in September of 2008. That might seem like a minor thing, but teams watch that sort of thing. By minimizing the number of days of service time, they can keep a player from reaching arbitration "too soon."
It's the business aspect of MLB that really can be tedious. If you take a look back at when Jon Rauch was added to the roster in 2005, it conveniently enough kept him from reaching arbitration eligibility