Can your running gait change?

So I've just managed to laterally sprain my ankle for the third time in the last few months (not always the same ankle). I've finally scheduled a visit with a physical therapist to figure out why this keeps happening, but they can't make room for me for a couple of weeks.

So in the meantime, I thought I'd throw this out to BT. I've run a marathon, done a half IM, and participated in several 10-13 mile races as well as various triathlons over the past 5 years, and NEVER had any issues with my ankles. But now all of a sudden it's one sprain after another, which leads me to wonder, is it possible for your running gait to change?

I've been wearing Asics Gel Evolutions for the past 2 years, and prior to that I wore NB stability shoes, though I can't remember the style. Each time I've been fitted, they've put me in shoes to counter my tendency to overpronate (and I've gone to different stores with different fitters). I really liked the Asics, so I haven't been refitted for at least two years.

Now I'm wondering if it's possible for running gait to change, and instead of keeping me from pronating the extra "support" could be now forcing my ankles into rolling the other direction.

Is it possible? I can't run and get refitted any time soon since I'm pretty injured at the moment, but wanted to see if BT had any thoughts or experience in this. Thanks! Sorry this is so long.