Published Aug. 7, 2014 9:43 p.m. ET

If you're reading this, you're probably well-familiar with Baseball-Reference.com, and you've probably gleaned any number of facts from B-R.com's play-by-play database.

What you might not know is where that data comes from: Retrosheet, a non-profit organization devoted to the propagation of baseball statistics and staffed entirely by volunteers. For some years, of the most productive of Retrosheet's volunteers has been Tom Ruane, who also writes the occasional essay about all he's learned. 

Tom's latest is about games that "broke" Retrosheet, and here's just a small bit about one of my favorite baseball obscurities ... the use of courtesy runners in league games ...

Retrosheet's web-site contains an article describing all of these courtesy fielders and runners (and many more), but I did want to mention one more game that caused my software to misbehave: the June 9, 1922, game between the Yankees and White Sox. In the sixth inning that day, New York catcher Wally Schang was hurt sliding into second and was replaced temporarily by courtesy runner Al DeVormer. So far, nothing too unusual. But in the eighth inning, Schang hit a one-out single and DeVormer was sent in to pinch-run for him for a second time. It is the only instance so far in our released event files in which a player pinch-runs for another twice in the same game.

Major League Baseball has certainly become more professional and formalized over the years, and on balance this is probably a good thing. But man, you sure could see a lot of strange things back then. For everything we gain, we do lose something.