I ended up a few plate appearances short at catcher in a theme league (no waiver wire/AAA) so I've occasionally been playing one of my other field players out of position. I started doing it with my worst pitcher, figuring it would be a disaster and I'd end up losing badly, but then this happened...
Bill Lee when pitching to Jose Iglesias as emergency catcher: 3-0, 3.57 ERA; Spaceman pitching to actual catchers: 0-2, 10.32 ERA
Iglesias hasn't been horrible, with two passed balls and an error in those three games, and he even threw out someone trying to steal!
https://www.whatifsports.com/slb/Boxscore.aspx?gid=34400179&pid=1&pbp=0&tf=10