Hangartner started 15 games at center in 2006 for the Panthers, but he has the flexibility to play guard.
Hangartner was one of the options the team was considering as a possible replacement during Weeks 1 and 2 while Jeremy Bridges is serving a two-game suspension.
"That's what the preseason is for - taking a look at guys in different spots," coach John Fox said. "You try to pick your 53 guys and we're trying to get that sorted out."
Teammate Mike Wahle said he believes Kalil will be a solid player in the league at some point.
"I thought Ryan did a good job, for the most part," Wahle said. "He's got some things he needs to work on certainly, but as does everybody. But for the first time out, playing with the ones, I thought he did a good job."