RH SPs with low 90s stuff are pretty fungible.
He may turn out to be a decent ML starter down the road, but Castellano will be 24 with little potential left for additional velocity at this point. You're probably looking at a 5th/6th starter as his ceiling in 2-3 years.
He only had 8 starts at AA, and didn't show much out of the pen in 2023, so he's a long shot to be taken, he's not going to start in the majors and probably has little value as a RP. You'd have to stash him for a year, then give him a season in AAA to polish his stuff, so maybe he starts for you at 26 or 27 years old.