[1][4] Working with coach Jimmy Johnson at Arkansas, Manor recorded 173 tackles during his junior and senior years.

[3] Afterwards, he received a call to play for the Ottawa Rough Riders of the Canadian Football League (CFL), but by the time he arrived, they said they no longer needed him.

[3] Manor was signed by the Denver Broncos in 1976 and made the team, but was sidelined for the year by a knee injury in the final preseason game.

[5] He made the roster in 1977 and played in 13 regular season games, helping the Broncos reach Super Bowl XII where they lost to the Dallas Cowboys.

[1][4][6] Manor played every game for the Broncos in 1978 and became a full-time starter the following season, having his best performance in 1979 when he made 6.5 sacks and a fumble recovery.