This is the first episode in which Dominic West does not appear. West requested less screen time for the fourth season so that he could spend more time in his London home with his daughter.
In "Cutty's" gym there is the old golden gloves poster showing Avon Barksdale, the one that Lester sourced in season 1.
In a DVD commentary track, David Simon said that Dominic West has a reduced role in season 4 because they only had him for two weeks total due to his shooting schedule for the movie "300."
Prez listens to Johnny Cash's "Ring of Fire" while cleaning a classroom. This mirrors a scene back in season two where he works while listening to Cash's "Walk the Line"