Ken Rosenthal has it from a source:
Losing Didi Gregorius is the big loss here. He has a tremendous glove at shortstop and has the raw tools to turn into a pretty good hitter. But those tools have not developed yet, and he seems to have a long way to go in that respect. Plus, Zack Cozart seems to have a decent hold on a position, so Didi was more or less expendable.
I like Drew Stubbs more than most Reds' fans, I suppose. It's tough to see him go because I think he still has some potential. Hopefully the Indians can fix whatever is broken and he can become a successful major leaguer. He seems like a good fella and he deserves it.
But yeah, this is a terrific move for the Reds. Big get, Walt.