Again, there's no concern with the 40 man spot, as the Brewers will have more 40 man spots available than they've had in years.
Now, your choices are Black, who might have a Sal Frelick like impact, or Rowdy. If Black doesn't hit, then he is Rowdy, except with speed and versatility. If Black does hit, and he is red hot in AAA, then he's exactly what this sad Brewers offense needs.
It would be ridiculous not to give him a shot considering how bad this Brewers offense is.