I’m sure there will be more information on this after today’s game, if not sooner:

He did make a dive in the middle innings last night in left field, and it looked like it yielded a pretty hard impact with the ground. Perhaps that’s it, and he started feeling the soreness today. Anything in that core area though – ribs, abdominal, back, oblique – and I get nervous for hitters.

Austin Jackson replaces Schwarber in the lineup for today. And we wait, nervously for more details.

UPDATE: Those details came quickly and they are mixed:

Any time a player’s discomfort is enough to get an MRI, it’s mildly concerning, even if the word “precautionary” is inserted. That said, if the hope is that he misses only today, rests tomorrow, and comes back on Friday, that at least suggests no one is expecting this to be a long-term thing. That doesn’t mean the MRI might not show something different or Schwarber might not feel even worse tomorrow. It just means that it’s reasonable to keep the Panic Meter at a low setting right now.