No one is giving up on him..I just think his stock has fallen.
But it's not because Sanchez has pitched terribly - it's the opposite. The other prospects on this team have shown a lot more development and stuff to the point that Sanchez is no longer untouchable.
I'm a lot more excited about the Mexican and the Castro because they both have shown excellent stuff and control.
Sanchez has good stuff. But it's not sexy. He has a high 90s fastball just like Castro and the Mexican, but unlike those two, Sanchez' stuff doesn't generate enough swinging strikes. And to make matters worse, Sanchez hasn't exactly improved on his control and command. A lack of control and command and stuff to K people out isn't encouraging.
Swinging strikes are not the be-all-end-all, but they are extremely helpful for a pitcher that can generate the K when needed. And they are especially important for relievers, who are often brought in for situations where a hold is required.
Sanchez needs more development of his off-speed pitches and control. The great thing is he's still young, so there is more than enough time for him to develop. But sticking him in the bullpen reduces the necessary reps and experiences that can help him if he were in the Buffalo rotation.