The Colorado Rockies are playing great baseball right now, and thus are starting to position themselves for a playoff run. In that, they recently traded for a pitcher from South Korea named Seunghwan Oh. He chose the number 18 when joining the club.
So in Korean, the way you say “eighteen” sounds pretty similar to the way you say the "s-word" in English.
So therefore his jersey reads "Oh sh*&."
No word on whether or not this was intentional, but I really hope it was...