In what has been a quiet training camp and exhibition season so far the Panthers have now suffered their first major loss. Jonathan Stewart can be a beast when he’s healthy – remember that 206-yard game he had against the Giants in 2009? But he hasn’t been healthy for a while now. Stewart was placed on the physically unable to perform list Tuesday meaning he must miss Thursday’s exhibition against Pittsburgh and at least the first five games of the season. His absence certainly isn’t unexpected but it is the most dangerous thing that has happened to the Panthers in the past couple of months. It’s more significant than firing Geoff Hangartner or figuring out that neither Joe Adams nor Edmund Kugbila will play for Carolina in 2013. Stewart may not play the whole year either – there’s no certainty that five games (and one bye) worth of missed time will get him healed. If he doesn’t play at all this year – and he won’t be eligible until the Oct. 20 game against St. Louis – then DeAngelo Williams sure better not get hurt. I’m fine with Mike Tolbert as a change-of-pace back but not the primary one and right now he’s hurt too with a hamstring problem (although he may be ready by the Seattle game Sept. 8). And Kenjon Barner Armond Smith or Tauren Poole? I don’t think any of them are ready to play a really significant role so that would be scary. So would Cam Newton leading this team in rushing again like he did last year because that opens the quarterback up to too many hits. The bottom line is that Tolbert needs to channel his inner Stewart which is possible – he also catches the ball and runs well between the tackles. Those who watch Panthers practice regularly have seen Stewart the Panthers’ second all-time leading rusher behind Williams in both yards and rush touchdowns grimacing in pain even after slight exertion. So obviously he’s not right. He had surgery on both ankles in the offseason. He also missed the final seven games of last year with injuries. Like Jon Beason he signed a huge contract extension not that long ago and has mostly been hurt since.