Kojima has come out and said that TPP and Ground Zeroes are actually two different games, and together the make up "Metal Gear Solid V"
He said it's "V" and not "5" because he's taking the series in a different direction. It will be open-world and has said the only playable character is Big Boss. Hmm...
12/07 - Exodus
12/08 - Blackalicious
12/11 - Saves The Day
12/16 - Pallbearer
12/18 - Orange Goblin OR Wolvhammer