The fact that he had surgery doesn't really tell me much.
Now I'm no doctor or professional, but I do know some about turf toe. Surgery is pretty common with this type of injury, but again, different strokes for different folks. Typically guys mid season try and play through it and miss here and there and never get a good rhythm. They end up worse off for it. Him taking care of it now will hopefully give him plenty of time to be ready for the season.
Without knowing the specifics of his injury, if he has been wearing a boot for a little while, I would guess he had this for a little while, it didn't get better, and the staff said go ahead and get it taken care of before the season starts. Good preventative measure for the long term in my opinion.