Yeah, I don't understand why people think development will stall if he's on the MLB team. Spending a season throwing low-leverage innings against the best hitters in the world, will also being taught by MLB pitchers and the organization's best coaches isn't exactly catastrophic for development.
And he at least has an off-speed pitch and control of an upper 90's fastball. It's not exactly a given that he'd get knocked around the park every time he pitches.