User blog comment:Aleksandr the Great/Prothean Squadmate is Officially DLC/@comment-1221773-20120222232942/@comment-1221773-20120223011127

We'll see just how involved the Prothean is in the core storyline when we get the game.

And BioWare said another team worked on the DLC, not another studio. This other team may be part of the Edmonton staff, working in the same building.