Why is Justin Turner's jersey stained

Pine tar stains the back of Los Angeles Dodgers third baseman Justin Turners' jersey during the second inning in Game 4 of the World Series baseball game against the Boston Red Sox

Justin Turner Authentic Game-Used Jersey from 5/11/21 Game vs. SEA

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

Why is Justin Turner's jersey stained

MLB free agency begins with Aaron Judge, Trea Turner leading the way

Why does Justin Turner have that permanent pine tar smudge over the TU on the back of his uniform? : r/Dodgers

Does JT Ruin Every Jersey of Every Game or What is their Laundry Department Using to Clean Them? I Need Some of That Detergent! : r/Dodgers

Justin Turner's jersey number might not sit well with Red Sox fans – NBC Sports Boston

Does JT Ruin Every Jersey of Every Game or What is their Laundry Department Using to Clean Them? I Need Some of That Detergent! : r/Dodgers

Why is Justin Turner's jersey stained