Why is Justin Turner's jersey stained

Why does Justin Turner always have a black smear on the back of his jersey? Superstition? Also, why do some players batting helmets have mud/oil rubbed on the front of them?

Game used, Justin Turner's jersey with pine tar stain and all😎 #Madew

Dodgers Star Justin Turner Has Unusual Jersey Modification

What causes the stain on the back of Justin Turner's jersey? : r/Dodgers

Why isn't Justin Turner still with Dodgers? Turner: 'I have no idea' - Los Angeles Times

Justin Turner Tar Stain Jersey Dodgers for Sale in Long Beach, CA - OfferUp

LA Dodgers x Justin Turner jersey 10 Promotional - Depop

Why is Justin Turner's jersey stained

The Sporting News on X: There's a very simple reason why Justin Turner always has a stain on his Dodgers jersey. 📰: / X

How Justin Turner gets the pine tar stain on his shirt.. #mlb #redsox , justin turner pine tar