A quick comparison ...
ERA WHIP K/9 HR/9 BB/9 K/BB H/9
Bailey 2004 (Low A) 4.43 1.46 10.85 0.43 5.38 2.02 7.73
Bailey 2005 (High A) 3.08 0.96 9.91 0.68 2.39 4.14 6.15
His sudden improvement in walk rate, to put it mildy, has been huge. He's cut his BB/9 rate in half while doubling his K/BB rate and maintaining his exceptional K/9 rate, which means he's simply gained control instead of sacrificing stuff for control. Hopefully Bailey keeps this up in Sarasota and his early start and newly improved control this season isn't merely a mirage.