I know this idea will not be popular with a number of individuals who are demanding that HB be brought up to the majors right now. However, here's what I would do if I was WK...
Today, August 1... Promote HB to AAA and let him make his next scheduled start. Let him continue pitching in AAA throughout August.
September 1... if HB continues to dominate throughout August, add him to the expanded September roster. If I remember correctly, potential playoff teams must have their playoff roster set on September 1. Let HB make 4-5 starts in September. His performance in September would then tell you whether or not he is capable of carrying this team in the playoffs.
That's what I would do... a bit of a compromise between bringing him to the majors now and forcing him to stay in the minors the rest of the season.