Before the readers freak out and explode the comment section, let me clarify that I don’t believe anyone in the MLB is truly untouchable. Well, maybe Mike Trout. Even the best and most-hyped prospects can still be traded at the right price.
Padre fans don’t have to be reminded of this. This past January, the Padres traded their top prospect and top-rated first base prospect, Anthony Rizzo, to the Chicago Cubs. Thought to be untouchable at the time, Rizzo was the main piece the Padres got in return of the trade that sent Adrian Gonzalez to the Red Sox.
Thus, as I create this list, I’d prefer for “untouchable” to be defined as “not likely to be traded”.
Honorable Mentions: Casey Kelly, Yasmani Grandal, Andrew Cashner (I don’t consider any to be prospects anymore)