ThisisXbox.com writer Jason Andrews met the voice actor of Captain Price, Billy Murray, recently while on a flight. While Andrew's talked to Murray, he had this to say, "On Monday I am off to meet Infinity Ward about the next game, Modern Warfare 4, I'm doing work on the sequel to Modern Warfare 3, it carries straight on and I only ever appear in the Modern Warfare games..."
His statements seem to confirm a few things, Call of Duty: Modern Warfare 4 is in development by Infinity Ward and will be a direct sequel to Modern Warfare 3, Captain Price will return, and Price will not be featured in Black Ops II, despite rumors of his inclusion.
Based on some previous news leaks and announcements, it looks like we won't be seeing this game until 2014, as Sledgehammer is developing next years game. I guess we will just have to wait and see.