First of all, the headline you’re seeing all over the internet is incorrect.
From our friends at CNN: “MLB has been around a long time. This had never happened before.”
The “this” to which CNN refers was a show-stopping 21-pitch at-bat between Los Angeles Angels pitcher Jaime Barria and the Giants’ Brandon Belt on Sunday, a real-life GIF in which Belt fouled off 16 two-strike pitches, 12 minutes and 45 seconds of tedium that no one who witnessed will ever get back. Eventually Belt flied out to right field.
Never happened before? It’s unknowable.