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Pick one to bring up. Likely scenario that he gets sent down in a couple months with a better understanding of what to work on and bring the next one in. If they're pitching with a quality you just can't deny, then oops you lost a year on that one and that ones a front runner for rookie of the year. Chances are they have their struggles and sending them back down pauses the clock again.
They don't have to stay down until June, any 2+ month period will work. This scenario isn't all that odd either, many pitchers have started out with the big club, gone down and come back.