Yes, Amir, if he signs with the Reds, can play in the minors and play for Coach Lavin, but why would he? As I, and a few other posters, have said a few times, the pro money is just not there now. Amir would get as much, if not more, baseball exposure at the college level than at the lower minor league level.
I do not think Amir, right now, has the pitching skill level necessary for the pros. He should give himself some time to work on these skills at St. John's. Who knows, by 2014 he may be a #1 pick and go right into the pros.