If they're using data to make the decision he is going to run out of innings before they are able to determine that answer. He needs to show he's clearly better than 13 pitchers on the 40-man roster, plus Festa, Ohl and the dozen relievers they have in AAA. That will need at least 50 innings in AA to get promoted and another 50 in AAA to get enough data to make the decision. Otherwise you're promoting based on potential and not results.
They only get to add a couple extra arms. They don't get to bring up the whole 40 man roster anymore.