When Chourio reached Low A last July, he became the first pitcher under age 18 in full-season ball since Julio Urías debuted in Low A in 2013. Chourio signed last January for $247,500, began in the Dominican Summer League, then moved to the Arizona Complex League, and between those two stops he walked one batter in 28 2/3 innings for a 0.9 percent walk rate. He finished the year in the Carolina League, where his walk rate soared to 4.2 percent (that’s sarcasm) and he did have real issues with men on base, giving up a .340/.389/.740 line in a small sample of 54 PA. He doesn’t look like a 17-year-old on the mound, certainly, with exceptional command of a three-pitch mix that includes a 94-97 mph four-seamer with some ride and natural cut to it, an upper-70s curveball that seems to drop off the table, and an 84-88 mph changeup with good fade that he almost exclusively used against lefties. He’s already stronger than his listed weight of 160, with a good lower half to maintain that velocity and perhaps add a little more as he becomes an adult. There’s obvious risk with any pitcher his age throwing even moderately hard, and he does have to pitch better from the stretch, but this is everything you’d want to see in a young pitching prospect, including the potential upside of 80 command.
