John Joseph "Jocko" Fields (October 20, 1864 – October 14, 1950) was a Major League Baseball player. He was born on October 20, 1864, in Cork, Ireland. Fields made his Major League debut on May 31, 1887. He played for the Pittsburgh Pirates, Pittsburgh Burghers, Philadelphia Phillies and New York Giants. Fields played 341 games in the majors, with 358 hits in 1,319 at bats. He had a lifetime average of .271. He had 12 home runs and 176 RBI. Fields died on October 14, 1950, in Jersey City, New Jersey.