When Stan Musial died, the grounds crew at Busch Stadium in St. Louis began drawing a number 6, the jersey number of the Cardinals Hall of Famer, on the back of the pitchers mound before every game. Before long, someone added a crucifix alongside Musial's number.
Now the Cardinals' front office has sent a message to the grounds crew: no more crosses on the mound. The reason, according to Crave's NESN website, from Cards General Manager John Mozeliak is simple inclusion. Mozeliak refered to team policy to not include any religious symbols in or on the stadium.
Guess if you want your Christianity reference while watching Cardinals baseball, you'll have to keep an eye out for the crosses around player's necks.