1. He's ready but could still tack on a few more points if he has it in him, the coaching in AAA is good enough and he gets enough innings.
2. The real issue is whether you need him. With 3 years of service, you'd be starting the clock "early". But he's 25, so you've got his most productive years under cheap control regardless. And it's always good to question whether you can get what your ML team needs out of another, less important to the future, AAA pitcher or trade market pickup, as opposed to the "stud" prospect.
So the question is - what do you need in the bullpen? Because to put Andrews or Shinjo in the pen means giving them innings - probably more innings than a traditional setup man. Both would be excellent "enter in the 5th, stay on until they hit 50 pitches" guys; 10-12 wins, 6-8 saves, 130IP (full season). But that might also lead to a a couple of "gas on a fire" appearances, too. Do you want Shinjo/Andrews to pitch more innings than your Closer or incumbent SuAs? (FWIW, I'm ignoring LRA because there's certainly a better option than wasting Shinjo/Andrews on those "every 4 -8 games, get 3 innings once the SP has already been bombed" situations)
Also, I'd see what I could get in trade for O'Rourke. He's a likely Type B, at least, so maybe someone makes an offer you can't refuse. Andrews comes up to replace him.