Well, generally speaking when MLB players are being evaluated in the minors regarding when they are ready to come back up, alot of it is process related rather than results oriented. If he's having great ABs and just finding gloves with his contact, it doesn't mean he isn't ready. What they want to see is A) is he having good PAs and making good decisions, and if they have recommended changes or adjustments, is he consistently showing those adjustments in his PAs.
The results are not the focus. Nobody on this board can speak intelligently as to whether he was ready to be called up or not based on a slash line and statements like yours above are missing about 99% of the information being evaluated, and are therefore... worthless.
That said, nobody realistically expects any player to get 3 hits in a game no matter who they are. There's lots of players who, if they do get 3 hits it's not a real shock, but expecting 3 hits in a game is not an expectation for any hitter.