Manor was selected in the 15th round (380th overall) of the 1975 NFL draft by the New York Jets.[4] He was one of their final roster cuts.[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] He ended up spending the year as a car salesman.[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.[1][4] He was a member of Denver until 1984, appearing in 102 games for the team by that time while posting 22 sacks.[1][4]
The Tampa Bay Buccaneers traded a future draft choice for Manor prior to the 1984 season.[7] He appeared in six games as a reserve, posting one sack, before being released by the Buccaneers, after which he was re-signed by the Broncos and finished the season with them.[4][8] He spent the 1985 season on injured reserve and did not play afterwards.[4][9] Manor finished his career with 113 games played, 35 as a starter, with 23 sacks, one interception, and three fumble recoveries.[4]