u/paygel

In the NFL, New York Jets QB Mark Sanchez stumbled into the butt of an offensive lineman, causing him to fumble the ball and allow the Patriots to return it for a touchdown. This happened back in 2012, and many people argue that this mistake was so bad that the Jets have still never recovered as a franchise. https://www.youtube.com/watch?v=82RIfy-gRa4

What would be the MLB version of the butt fumble? As in, what single mistake did a team/player make that was so bad, that their team arguably hasn't recovered from the impact of that mistake since.

I'm a huge fan of the NFL but I don't know much about the MLB, so I'm curious.