#3 Surprise member of Team SmackDown
Although the members of Team RAW and Team SmackDown have already been announced, there is still plenty of time to go until Survivor Series where the status quo can be disrupted.
Should CM Punk and WWE agree for him to return at the event, any one of the members in either team can be replaced and convincingly so. Given that he will be a part of FOX's WWE Backstage show, however, it makes more sense for him to join team blue.
The Superstar he would be replacing could be written off due to 'injury', bow out of the team because of in-fighting or just flat out refuse to represent the brand...take your pick.
And there are sufficient episodes of RAW and SmackDown left before Survivor Series for the story arc to be told convincingly and make sense too.
That would conveniently leave WWE with a mystery team member to announce heading into the event.
No prizes for guessing who.