Could just be the yips. I know it's absurd to compare D1 football to beer league softball, but one year I was on a team with no pitcher. We kept having different guys try, no one could hit the strike zone and we walked a lot of guys. One day I said "it's just lobbing a softball into a big strike zone, how hard can it be" and volunteered. At the start, it worked great. I hit the strike zone consistently and our problem was solved. Never thought too hard about it, just started throwing the ball.
A few months later, everything went to hell. Not only was I missing, every time I let go of the ball, it felt like I did it wrong. I started trying to think more about my mechanics. That made it worse. It felt like I was gripping the ball wrong, releasing it at the wrong point, but I couldn't figure out what the right way was. At one really low point I was on the mound and wondered if I had stayed stepping with the wrong foot, and then realized at the moment I couldn't even remember which foot I stepped with.
It happens with high level athletes. Golfers. Chuck knoblauch. Something gets messed up, you start thinking, and the harder you work, the worse it gets. Have to imagine Kesich is even more frustrated than any of us (well, probably most of us based on some of the threads).