One better-than-average month does not a prospect make.  Unless the pitcher in question is a former lights-out can't-miss left-handed super-prospect coming off of major injury and even worse control issues as he settles into his old pitching motion.  I'm going to declare:

Greg Miller should be back on the prospect radar.

Reliever?  Sure, and most pitching prospects aren't.  Pressure situations?  Maybe not, but any time someone trying to get over having the K:BB ratio he has had for 2 years is feeling the pressure with every pitch.  Performance?  Okay, he hasn't quite put the walks completely behind him.  But for a one-month stretch, Greg Miller appears to have finally found a rhythm, and his performance is starting to show increasingly positive results.  Consider since May 10th:  8 appearances, 10 IP, 5 H, 6 BB, 13 K.  That is a 1.10 WHIP, fanning more than a batter per inning, at the Triple-A level in a horrible pitcher's park. 

Does this mean that he should get the Joba treatment from Joe Torre and jump into the saddle in LA?  Heck no.  Is he a better pitcher today than Seth McClung at 24?  In my opinion, yes.  Could the organization groom Miller as the eventual heir to Takashi Saito, or even Jonathan Broxton?  Perhaps.  He's 24, he's got plenty of arm left, and he can strike guys out. 

What role, if any, do you see Greg Miller filling for the Dodgers in the next 3 years?