User blog comment:Aleksandr the Great/Prothean Squadmate is Officially DLC/@comment-1440333-20120223192334/@comment-4491632-20120223205819

Brings up a good point, actually, which would still allow the Prothean to be an important part of the story without having to make it bloody DLC. I can imagine him being in the squad for one mission, much like Anderson was in the singleplayer demo, but not being a full squad-member. After all, as the last prothean is important. If I was the last human I wouldn't be throwing myself into the middle of a firefight at any given chance.