Daniel Lee Dierdorf (born June 29, 1949) is a former American football offensive lineman and current sportscaster. A native of Canton, Ohio, Dierdorf played college football for the University of Michigan from 1968 to 1970 and was selected as a consensus first-team All-American in 1970 and a first-team All-Big Ten Conference player in 1969 and 1970. He was inducted into the University of Michigan Athletic Hall of Honor in 1996 and the College Football Hall of Fame in 2000. Dierdorf played professional football in National Football League (NFL) with the St. Louis Cardinals for 13 seasons from 1971 to 1983.

On September 9, 1979, Dierforf sustained torn ligaments in his left knee during an extra point attempt in the second quarter of the second game of the season against the New York Giants. After the game, Dierdorf said, "The knee was completely out of the socket. It moved a couple of inches off to the side. My leg was all twisted around and my foot was pointing in the wrong direction. It was painful. Very painful." Dierdorf was carried off the field on a stretcher, underwent knee surgery, and missed the remainder of the 1979 season.  Dierdorf returned to the Cardinals in 1980, starting all 16 games for the team at right tackle in both the 1980 and 1981 seasons. In 1980, he was selected to play in the Pro Bowl and was selected as a first-team All-NFL player by the NEA. In 1982, Dierdorf moved to center and was the starter at that position for all nine games in a strike-shortened season.  In 1983, Dierdorf returned to his right tackle position and appeared in seven games, only four as a starter. On October 11, 1983, after the Cardinals began the season with a 1-5 record, Dierdorf announced that he would retire at the end of the 1983 season. At the press conference announcing his retirement, Dierdorf said, "This was an easy decision for me to make. . . . Physically, I just can't play the type of game I want to." He added: "Ninety-five percent of me is sad that I'm retiring, but my knees are very, very happy."

Did anything happen significant in the 1979 series?
Dierforf sustained torn ligaments in his left knee during an extra point attempt