Hangartner is an experienced center with several starts at the position while also being a long time back-up for the position.

Carolina Panthers: Geoff Hangartner in the Spotlight
Although, he wouldn’t start at or even play center again until he joined the Buffalo Bills in 2009. Hangartner would serve as the Bills starting center for a full two seasons before finally being released by the Bills prior to the kick-off of 2011.

Hangartner rejoined the Panthers and return back to playing right guard alongside Kalil all of last season. Hangartner’s transition back to center will of course be challenging, but the good news is that Panthers quarterback Cam Newton is familiar with him. Hangartner protected Newton all throughout Newton’s rookie season playing on Carolina’s offensive line.

Kalil was a Pro Bowler for a reason and he will be missed. I still trust the offense will run as smoothly with Piggy at center as it did with Kalil...not that the bar has been set real high in the 'smooth' part.