Board Thread:Manga/@comment-31209938-20170202034645/@comment-27441457-20170202210935

I've had the assumption for some time now that the power of Zeke's Titan is to create other Titans, like how the Founding Titan can manipulate memories and actions and how Annie's Titan can attract Titans in large numbers.

And based on how there were no Titans present at Shiganshina when the Survey Corps arrived, it's also very possible that Zeke could have used his power to take those Titans at Shiganshina and "store them away" until the time came for the battle.