I don't think so. When you sign in to steam you have to be online, then you can go offline after that. Also in past games zombies and combat training required an internet connection, even if you were playing by yourself. I don't know if it is like this for squads or extinction mode. If you can get steam to work offline you should be able to play the campaign, but that will probably only be about 4 hours long. I really love this franchise, but unfortunately if you are getting rid of your internet connection it is probably best that you skip this game and buy something else.
If you really want to play COD, the first Modern Warfare and World at War don't use steam, so you can install them on more than one computer. The updates and map packs are free and you don't need an internet connection to play zombies, or even multiplayer, so if you install the game on multiple computers and if you have a local network you can still play multiplayer when your friends visit without needing to buy several copies of the games.
You may just need a connection upon install, and then go offline forever after that. This won't help you prior to release but as soon as I get the game I will report back with if this is possible or not.
The campaign, extinction mode and squad mode are the possible ways to play offline. I will check each out and let you know.
It doesn't appear squads will be available offline, i just tried it and i only can select 'options' and 'online squad play' wont give me an option to go offline, and when in offline mode i try to go to online squad play it says i need to be in online mode.