Quarterbacks coach Byron Leftwich, a former 10-year NFL veteran, was promoted to offensive coordinator.
The Cardinals looked completely inept on their home field in a 45-10 blowout loss to Denver. Rookie quarterback Josh Rosen, selected 10th overall by Arizona, threw three interceptions - including a pair of pick-6s in the first quarter - and lost two fumbles.
McCoy's tenure with Arizona lasted just seven games. The Cardinals rank last in the NFL in total offense, third-down conversion percentage, and rushing yards per game. They're second-last in passing yards per game.
Members of the Cardinals organization were reportedly frustrated with McCoy's mundane play-calling, his inability to get running back David Johnson going, and the amount of responsibility he gave Rosen, according to NFL Network's Ian Rapoport.
After Thursday's game, first-year head coach Steve Wilks said it was "premature" to consider making major changes, but acknowledged he was embarrassed by the outcome.
Arizona has earned just one victory in its first seven contests.