If this is true, I would have to guess it's because of BFV and it's rumor being true as well. Battle Royale makes way way more sense in Battlefield, mostly due to it's massive multiplayer maps. If Activision got wind that EA was having Dice add this mode into BFV, I'd have to assume with it's popularity, there's no way Activision would allow them to have an entire year to themselves over CODBOIIII.
This would also be a justifiable reason to drop the campaign for COD, or sell it as DLC later. Battlefield campaigns have never been all that great overall, so dropping it shouldn't be that big of a deal with another mode to replace it, so that's another reason Activision can use to justify dropping it from COD. Not like COD's campaigns have been that great recently either. If BFV has a campaign as well though, it would look pretty bad on COD for dropping it completely, unless the price matches the content.
