See a physio for a proper diagnosis but it could be a problem with the calf. Make sure that you stretch the calf properly before a game (and after, too). I had a similar problem and it was explained to me that the muscles and ligaments were too short between the back of the calf, the achilles and the foot. This had changed the angle of my foot (very slightly) and placed more strain on the muscles and ligaments in the foot (they were having to work hard to maintain shape). I did stretch exercises twice daily for a few weeks to alleviate.
Incidentally, have you changed anything recently? New car, job, walk to work instead of drive (vice versa), new sofa, different work chair/desk etc? Sometimes, these things can have an impact on the body which we don't imagine.
Just a thought but as I say, see a physio.