For those who want to go right inside baseball, the rarely called error of balking is a study. A pitcher was previously allowed to feint toward third (or second) base, and then turn and throw or feint to first base if his pivot foot disengages the rubber after his initial feint. This is called the “fake to third, throw to first” play. However, Major League Baseball classified this as a balk beginning with the 2013 season. It happened Saturday when Roberto Osuna committed a balk and the penalty was a run as Boston got to walk home Mookie Betts from third to tie the game. The Jays finally won it but the error seems both careless and complex. Here is a neat video showing pitchers getting caught balking. Watch for the game that is won when the man on third walks because of a balk.
https://www.youtube.com/watch?v=t4fjl2ANsh0