Redistricting may eliminate a district from Ohio and also the state will be redistricted. It really depends on who writes the new districts.
OH has a decidely GOP Legislature with a Dem Governor, sounds like Incumbent-Protection to me...
My guess is, Columbus is currently split in three and is growing fast. I bet the district lost comes up from the North, and they will merely hand all of Democratic Columbus to Kilroy now that there is a Democrat to protect in the area. The Republican seats will move towards the lost seat in the Iron Belt area.