The DBacks are really struggling to get much out of their pitching prospects this season. Pfaadt has given up 6 homers in 9.2 IP and is generally just getting completely destroyed lol, he's 1st percentile in just about Statcast metric. Hasn't struck anyone out, the fastball has a ton of spin (89th percentile) but it's coming in at an unsexy mediocre velo. Ryne Nelson and Drey Jameson are two others who are top 100 prospects coming into the season who have not debuted well at all.
Corbin Carroll is at least a stud, but Alek Thomas kind of blows, Moreno has no power but is otherwise pretty good, and Geraldo Perdomo would be awful if he wasn't running a .455 BABIP, he's outproducing his xWOBA by 150 points. Certainly too early to call any of them busts, but not showing promising results early on. The downsides of prospects.