FOX did not give an official reason why it won't air the new episodes this Sunday but it is thought that the network tries to avoid anything insensitive.
The shooting massacre in Connecticut prompted FOX to pull this upcoming Sunday, December 16 episodes of "Family Guy" and "American Dad!". The network did not give a reason but it's most likely they want to avoid airing any insensitive content following the Friday incident at Sandy Hook elementary school in Newtown, CT.
The new episodes of "Family Guy" and "American Dad!" will be replaced by repeats of "Grumpy Old Man" and "Wheels & The Legman and The Case of Grandpa's Key" respectively. Meanwhile, a 7 P.M. repeat of "The Cleveland Show" titled "Die Semi-Hard" has also been pulled off and will be replaced by another repeat titled "Menace II Secret Society".
New episodes of "The Cleveland Show," "The Simpsons" and "Bob's Burgers", which start at 7:30 P.M. are still scheduled to air.
This is the second time "Family Guy", "Cleveland Show" and "American Dad!" had been pre-empted due to unforeseen real life tragedies. Back in April 2011, the shows were scheduled to air a Hurricane-themed crossover but dozens of tornadoes devastated the South that same month. The episodes were shelved and only aired in October 2011.
The same move has been taken by Syfy which pulled an episode of "Haven" about a school violence. Meanwhile, Paramount canceled the Saturday premiere of Tom Cruise's film "Jack Reacher" in Pittsburgh.