Midseason replacement

A midseason replacement is a program scheduled to premiere in the middle of most other programs' seasons. While most shows premiere in September, the networks anticipate having to cancel one or two before the season has ended, so they prepare midseason replacements to occupy the time slots vacated by the cancelled shows. They are generally new shows, but sometimes returning shows get tasked as midseason replacements (such as Scrubs, which did not premiere with other NBC shows in the Fall of 2005).