If they don't pick up his option, you can pretty much write him off as a Spur. There will be a ton of teams with cap room next year, and one of them will almost certainly make Ian an offer. , a team without cap room could steal him with a fractional MLE offer if the Spurs aren't willing to pay him a salary slot of $1.75M, a team like CHA and Larry Brown, who have been drooling over him.
I think Mahinmi's "development deal" was pretty much terminated when they signed Ratliff. When the team signs a veteran player who has the exact skillset they want you to develop, and that development has been slowed or hindered, it's never a good sign. Same thing with Bogans/Hairston. At this point, other than Hill/Blair, I don't think the Spurs GAF about anyone else's development. They're in a WIN NOW mode.