Johnny Unitas wore it, and then they retired the number after he retired.
Peyton Manning was the only player to have worn number 18 for the Indianapolis Colts. After leaving the team, his number was retired.
In 1980, Terry Harper, an out-fielder, had number 19.
The highest number a quarterback can wear in the NFL is 19, which was worn by Johnny Unitas, who played for the Baltimore Colts.-----The highest jersey number that I can remember was #60 worn by Otto Graham of the Cleveland Browns of the All-American Football Conference. John Hadl of the Chargers and Rams wore #21 during his career in the 60s and 70s. But since the merger in 1970, the highest number a quarterback on the roster can wear is 19.
# 76 Dan Federkeil Tackle from the University of Calgary
Dwight Yorke for Manchester United
Robin Yount - Milwaukee Brewers
Joseph Addai (number 29) joined the Colts in 2006.