In a series of candid, detailed descriptions shared on social media Wednesday, Adam Wainwright traced what caused his delivery to go haywire in September to a moment in August that at the time seemed like no bother at all. During a start against Atlanta at Busch Stadium on August 28, Wainwright took a groundball off his left knee. The “comebacker,” as he called it on Twitter, came off Austin Riley’s bat at 103.5 mph — one of the hardest hits of the game — and after it ricocheted off his knee Wainwright scrambled over to retrieve the ball in front of the mound and whipped to first to get the ou…