Frederick Joseph Crolius (April 19, 1876 – August 25, 1960) was a professional baseball and football player. He is best remembered as being the first player from Tufts University to come to play Major League Baseball. He was at Tufts in 1894, and at Dartmouth College, where he also played college football, from 1896 until 1899. He spent two years in majors with the Boston Beaneaters and the Pittsburgh Pirates. Crolius also played pro football with the independent Homestead Library & Athletic Club and the Pittsburgh Stars of the first National Football League. He later served as a coach for both sports after his playing career ended.