He is said to have a fastball that can reach the low nineties and has good control to both sides of the plate. High school pitchers can always be kindof a crapshoot so if the Rockies think they saw something in Castellani (which they clearly did taking him this high) at least their third pick is a good place to go high-risk, high-reward.
I had kinda hoped that the Rockies might go after Mont'e Harrison with this pick but it sounds like there may have been an issue with signability.
Ryan Castellani has a 3/4 arm slot and is said to have a very mature approach to pitching so it's possible the Rockies see a possibility of repeating the type of success they have found with similarly profiled Daniel Winkler.
He throws a fastball, slider, curveball, and change and is likely to start in Grand Junction this season.
Here are some thoughts from David Hood (AKA David OhNo) on Wall:
With the Ryan Castellani selection, the Rockies are following through on their commitment to develop arms in the manner they feel will be best equipped to handle Coors Field. Castellani's strengths are closely tied in to the Rockies' pitching philosophy preached over Spring Training, that being the use of a heavy two-seam fastball down in the zone to limit hard contact. The rest of the picture, however, requires some development time.
Castellani almost fits the exact profile of the sinker-slider pitcher, except his arm slot is a little higher. With a great frame and room to add strength, Castellani has the height to create a natural plane to drive the fastball down in the zone, which he appears to do regularly. I don't see anything in his delivery I find particularly offensive or concerning, and the ease of which he delivers the ball suggests he may have more velocity down the road.
The knock you read on Castellani is in his secondary pitches, and in the videos available, it's hard to see much of either his curve or his change. Castellani is almost an open canvas for the development team to refine a breaking ball or alter the change-up grip, etc. Because he lacks the power of pitchers going around him, Castellani may require a bit more time in the lower levels before starting his climb, and he probably doesn't project more than a #3 or 4 at this point, but making any guesses to his ceiling right now can be a foolish exercise.
So height-plane-sink, something we've heard/read a lot, and now something Colorado looks to be adding to its drafting strategy.