Q: I heard you discussing the phrase “charley horse” on the air and you said the origin was unknown. I looked it up on the Internet and found that the original Charley was a lame horse that used to pull a roller across the infield in the 1890s at the old Chicago White Sox ballpark. I hope this helps.
A: Several listeners messaged me with various explanations from the Internet, some more interesting than others. Yours is among the more interesting, but unfortunately the term “charley horse” was in use before the 1890s.
The Oxford English Dictionary has published references from the 1880s, all of them related to baseball. Both the OED and The Random House Dictionary of the English Language say the origin of the phrase is unknown.
Another explanation, which comes to us via H. L. Mencken, traces the expression to Charley Esper, a Baltimore Orioles pitcher who was said to walk like a lame horse. Unfortunately, the term “charley horse” was in use before Esper joined the Orioles, according to the The Mavens’ Word of the Day, which cites The New Dickson Baseball Dictionary.
One more interesting explanation, from the American Dialect Society’s archives (via Michael Quinion’s World Wide Words), traces the term to the pitcher Charley (Old Hoss) Radbourne, who reportedly had a muscle cramp during a game in the 1880s.
The chronology is right, but I still think this is one of the many cases where we may never be certain about the origin of an expression. Or, as Quinion puts it, “We’re not sure where it comes from, but there are lots of theories.”