John Craig "Sky" Hertwig (January 15, 1952 – May 30, 2012) was an American professional football offensive tackle who played three seasons with the Detroit Lions of the National Football League (NFL).

He was selected by the Lions in the fourth round of the 1975 NFL draft after playing college football at the University of Georgia.

John Craig Hertwig was born on January 15, 1952, in Columbus, Georgia.

[2][3] He earned AP and United Press International first-team All-SEC honors that year as well.

[4][5] Hertwig was selected by the Detroit Lions in the fourth round, with the 94th overall pick, of the 1975 NFL draft.