Why did the Reds get Mark Teahen from the Diamondbacks for a PTBNL or cash?

For some reason, the Reds picked up Mark Teahen from the Diamondbacks in exchange for whatever. Teahen has spent the young season with the Diamondbacks' AAA affiliate in Reno, slashing .211/.318/.254. He spent all of last season with the Nationals' AAA affiliate and didn't fare much better. He can play all over the field, so his defensive versatility is really his most attractive feature.

I'm assuming Teahen will head to Louisville, where a number of injuries and call-ups have depleted the squad. I suppose there is a possibility that he could make his way onto the big-league club with all of the issues in left field, but I would prefer to keep Derrick Robinson and Donald Lutz on hand. But if the Reds think Lutz would be better served playing everyday rather than serving as the team's fifth outfielder, I guess I can't complain if Teahen is sitting the bench and getting a few pinch-hit appearances a week until Chris Heisey comes back.

Teahen used to be pretty good, and he's still only 31. In a four-year stretch in Kansas City from 2006-09, he hit a respectable .274/.335/.428 while playing every position but catcher, pitcher, and shortstop. He likely won't do that again, but the organization is hurting for depth right now and he's another warm body. I'm going to say that this isn't a big deal, but if it becomes a big deal, then the Reds have bigger problems than this being a big deal.