hmmm. You don't need to be martyred to become a saint, though it helps (the founder of opus dei is well on his way, and he died in his bed).
Here's a thought: Galileo was a devoted mathematician as well as scientist. Assuming the Renaissance church is just a bit more Pythagorean (say, Pythagoras' writings have a wider influence in Antiquity, or the manuscript survival patterns differ, or maybe the celestial mechanics are better understood and thus it is an accepted fact that God writes in *complicated* maths)
Thus, he could well use his considerable mathematical skills as what might be called a theologian. If what I read is correct he was a bit of a rigorist, loved to dispute, and overflowed with interesting ideas. As the spiritus rector of a seminary, he could assemble a devoted following of priests who pursue God through numbers. A few decades after his death, mniracles are sure to accumulate.
On an unrelated note: my spellchecker insists that 'Opus Dei' should read: Opus, die. A snide comment on 'Bloom County', perhaps?