While I don't believe 'untouchable' is a thing, I think a large handful of the game's best prospects are about as off-limits as it gets this summer.
Jackson Holliday is going nowhere. Junior Caminero is staying put. The Nationals aren't parting with James Wood, the Tigers aren't moving Jackson Jobe, and so on.
But there are contending clubs with highly-rated prospects that may very well be on the table if the right significant piece is dangled in front of them this summer.