In a way, you can probably say that. The determinism according to which it is impossible to have free will is always a system which is in some way closed. According to this view, everything is somewhat determined, so you can create a finite set of possibilities here. Of course, there are various versions of determinism, so I'm writing very generally now.Is Free Will possible because of Infinity?
On the other hand, in an indeterministic system, where there is a concept that free will is possible, we usually deal with an infinite number of possibilities.