I already discussed how free will does not appear as much a crucial conundrum, if seen from the point of view of Indian philosophy, which in general silently embraces compatibilism (between determinism and free will).
In addition to the general points already brought forward, it is worth remembering that Mīmāṃsā authors in general tend to favour accounts which mirror one's experience. If, for instance, one experiences one's cognition of a chair one gradually distinguishes in a dark room as a ''sense-perception'', there should be very strong reasons to refute it this status (see Taber 2005, discussing this point in Kumārila). Similarly, since we obviously feel that our will has a role in the process of undertaking an action, Mīmāṃsakas do not dispute this. Unlike their Western colleagues, Mīmāṃsā philosophers do not question the degree of freedom of the decisions one experiences as free. They do not, e.g., argue for the fact that our experience of freedom might just be an epiphenomenon accompanying the process of undertaking an action, or that our experience of freedom might be in fact a fake, since our decisions are completely determined by who we are, which is a priori determined by facts we cannot interfere with, such as genes and early education. The fact that decisions are experienced as free is enough for Mīmāṃsā authors to treat them accordingly.
Thus, for Mīmāṃsakas the issue of free will strictly depends on how one understands action. Within this framework, one could also just speak of ''will'', since from the point of view of the way a single action is caused, nothing changes if the general laws of the universe allow freedom or not.
On the topic of free will, a very recent article by Johannes Bronkhorst ("Free Will and Indian Philosophy", Philosophia Antiquorum, forthcoming) also argues in favour of an experiential approach. In our experience, we all know what it is to be free and this experience is perfectly compatible with determinism, since (see this post), we would keep on feeling free even if determinism were the case.
On free will in Indian philosophy, see this post (and the others tagged "free will").