Thats a big statement. So decoding that, what does that mean overall? What do they need to sell to be the biggest game of 2010? If we count both COD titles then they would need between 13M units *COD 6M 360 4.5M PS3 and 1.5M others* to 16M (COD 8M 360, 6.5M PS3 and 1.5M others) and thats assuming there isn't another title that sells more.
Its possible for them to sell 13M units, heck even 15M is within the realm of possibility but it would be quite a stretch to get that far. Halo: Reach would have to be the impact of Halo: CE to the gaming public to do that.