From the yu-gi-oh tagforce 4 forum on gamefaqs: This game is base on the OCG. XX-Saber Gardestrike is a TCG exclusive and was not in the OCG Ancient Prophercy set. It probably won't appear in a Yugioh game until the OCG gets Extra Pack 3. Not sure if it applies here apparently it's also an english only card, so it may not be in japanese games no clue if those reasons apply here though.
