Circling back with info I learned elsewhere, in case y'll haven't heard.
This "minor hand procedure" was indeed minor: simply removing the single metal staple that had been inserted in the surgery earlier this spring. It was done in 20 minutes yesterday. The rate-limiting step for a return to swinging is just how soon the incision location heals up.
It seems there's a possibility that this meaningfully improves his comfort swinging. As he exerted a lot of force in a swing, the staple had to flex around those mobile mid-hand bones, causing pain. And then there's the secondary effect of inflammation from that mechanical irritation, plus perhaps some inflammation from the body rejecting the material of the staple.
The main thing is that this talented youngster figures this out long-term, for what could be a very long and special baseball career. It's been a full year-long injury already, all from a HBP against Missouri, for pete's sake! But I was encouraged even in the short term, for his contributing to a title run this season, with the simplicity of the procedure and return timeline... and the possibility that the pain might have been as simple as side effects from the staple, which is now gone!