This is not something you normally hear about for any athlete, but especially not an 18-year-old:
According to one of my MLB sources, Braves top draft pick LHP Kolby Allard had surgery on his back after he was shut down in GCL this year.
— gondeee (@gondeee) November 19, 2015
Allard apparently had two vertebrae fused in his back. He was already a high-risk, high-reward pick, now leaning more toward the risk side.
— gondeee (@gondeee) November 19, 2015
Full credit to Martin Gandy for getting this information out: this has been hidden from view since August, when the GCL short season finished up.