After airing a two - hour comedy block on Thursday for 21 straight seasons , NBC broke with tradition in 2004 by replacing the 9 p.m. hour with the hour - long reality competition program The Apprentice .
NBC 's Thursday night lineup NBC 's its top 20 position .
After airing a two - hour comedy block on Thursday for 21 straight seasons , NBC broke with tradition in 2004 by replacing the 9 p.m. hour with the hour - long reality competition program The Apprentice , although its Thursday night lineup retained its top 20 position .