Frederick Joseph Crolius was an American football and baseball player and coach. He was the first player from Tufts University 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 of both sports after his playing career ended.

The 1901 Homestead Library & Athletic Club football team won the professional football championship of 1901. The team was affiliated with the Homestead Library & Athletic Club in Homestead, Pennsylvania, near Pittsburgh. The team featured a lineup of former college All-Americans paid by Pittsburgh Pirates' minority-owner William Chase Temple.