Andrew McCutchen says he has a broken rib, not an oblique strain, Travis Sawchik tweets. Dejan Kovacevic was the first to report that McCutchen did not actually have an oblique strain, as was originally reported.
McCutchen still has not been placed on the disabled list -- he apparently hopes he can come back quickly. We'll see if that's possible, or if the Pirates just end up burning a roster spot for a few days, but if there's any reasonable expectation that he might be back in, say, a week rather than a month, that's great news.
In any case, the fact that McCutchen's injury is a broken rib, and not a strained oblique, likely means that it was the Diamondbacks' petty retaliation that hurt him (although, to be clear, we don't know that for sure). Paul Goldschmidt's injury is a shame, but it was clearly the result of an accidental HBP. This one was intentional, and both the Pirates and the game as a whole are worse off for it.