This is a good write-up, and he's an exciting prospect. Adding him to the 40-man is an absolute no-brainer in the off-season at the very latest. Even if Donaldson isn't traded, he's getting older and could probably stand to take up to 25% of his games at DH. Miranda can also spell Arraez and Kirilloff against tough lefties and DH some himself. If the team somehow has zero injuries, then it will be a good problem to have. The likelihood of that happening when you have Arraez, Donaldson, and Kirilloff on your team is virtually zero though. Miranda could also just rake AAA for another year. He's young enough and has three options. I wouldn't call it service time manipulation either, because he is legitimately blocked by one or more players at all his positions right now.