When to promote prospects?

[allstardad]

Do you guys play through Spring Training to get an idea of how prospects perform against ML competition? I do this and then write down guys that can contribute and guys that I feel like I would be wasting a roster spot for, I put on trade block to see what I could possibly get in return.

[Friar Fanatic]

A really key thing to remember when calling up prospects is Super 2. That's always my number one concern.