User blog comment:Argorrath/Sledgehammer Games claims to be working on a new MW game/@comment-5290320-20130718211454/@comment-3967954-20130718213053

Frost was likely W.I.A. Although it's pretty obvious the real reason he didn't appear in Down The Rabbit Hole is because IW didn't want to make him into an NPC, since they're for some reason adamant that the American protagonists are never seen in third person.