mmk you're probably right. I noticed the callus getting thick. Probably need to file it down every once in a while.
TennisLova I'll have to give that a try if the filing doesn't work. I would think the Vaseline would make me slip a little more inside my shoes with the constant shifting.
Max I'm not sure it is actually tennis related. I've been playing a 4-6 days a week for a very long time and this is only the 2nd time I've had this develop. I do those things to avoid foot issues so when they come about I try to get to the bottom of it.
Just wondering if there were shoe suggestions better than the NB that add more cushion under the balls of the feet.