"Due to a legal dispute between the game's publisher Activision and the former co-executives of Infinity Ward - which caused several lay-offs and departures within the company - Sledgehammer Games will assist in the development of the singleplayer, and Raven Software will develop the multiplayer." Source - http://en.wikipedia.org/wiki/Call_of_Duty
Activision have proven time and time again that all they care about is selling more games. thi isn't too shocking really.