The Marlins did this to keep Hand on a normal starting everyday pitching rotation. Had the Marlins not sent him down, it would've been about 10 days before he started again. And that is not something you do with a 21 year-old arm. It is important to keep him on his normal starting routine. To take his place on the 25-man roster the Fish called up Chris Hatcher.
You remember Chris, he was called up as a catcher in 2010 and got a little playing time. While he only appeared in five games and didn't get a hit during any of those, he did exhibit a very strong arm. So the Marlins converted him to a relief pitcher. In Jacksonville this season he was 2-1 with a 2.31 ERA while posting a 10.03 K/9 and 3.86 BB/9. In other words, he throws hard but isn't always around the plate.
The good news for Gaby is that he is no longer the emergency catcher.
It will be interesting to see Hatcher's delivery to the plate. Normally a catcher who are converted to a pitcher will have a very short-arm delivery. It just goes with the territory.
Don't expect Brad Hand to return to the rotation anytime soon. The Marlins are trying to stretch out Clay Hensley while he is rehabbing with plans of using him as the fifth starter. Hensley was a starter for the Padres back in 2006 but that was more than a few years ago. He has the stuff to start, but should the Marlins decide to do this, and it appears they are, it could prove very interesting.
Personally, I would've stretched out Burke Badenhop. But K-Lay will probably do fine.