Here's an article by Peter King which suggests that Manning's conditiion is serious:
Manning's streak, and Indy's season, could be in major trouble.
Radio reporter Jon Michael Vincent of ESPN 1070 in Indianapolis reported Sunday night that Manning would need another neck surgery and would be out indefinitely. That prompted my call to Polian, who said he knew nothing about it.
This is what I know this morning: Manning, as you can figure, has been working like crazy to get his neck and right arm back to 100 percent. He had surgery 15 weeks ago today to repair a herniated disc in his neck, which had been causing pain in his throwing arm. When such a surgery is done, part of the disc is removed. That lessens the pressure on the nerve. But that nerve needs time to heal.
One neurosurgeon in Pennsylvania told SI.com's Will Carroll in August that such a healing could take up to two months. Clearly, that timetable has been exceeded. Why? We don't know. When I was in Colts camp three weeks ago, Polian and his son, GM Chris Polian, both told me they had to simply let nature take its course -- and then they went out and signed Collins for insurance because they didn't know when Manning would be back.
Manning has been able to throw, I'm told, but not with the same zip or as long as he usually does at this time of year. That's normal, to be sure, for a guy coming back from a serious neck procedure. It's not good enough to think he can play in six days.
But I'm told that Saturday, when he reported to the Colts for his normal rehab work, his back hurt. And that pain was more acute Sunday. So it seemed natural for Manning and the Colts to call in the experts who had been consulting on his case for more discussion, which seems likely to occur today or Tuesday. Polian didn't want to discuss the case, but this much seems sure: The radio report may be premature, but there is definitely cause for concern about Manning's short-term recovery and when he might play.
My guess? Manning has been rehabbing to excess, which may have caused the flare-up in his back. It may not have; that's simply my guess. And no, it's not a spinal stenosis condition, like the one that ended his brother Cooper's football career. Peyton was tested and cleared at the combine years ago. Maybe he needs to have the herniated disc shaved down a little further. We just don't know. But whatever is happening, Manning cannot throw the way he needs to throw to win an NFL game right now. You can't make definitive predictions about nerve recovery the way you can with, say, a broken leg.
Read more: http://sportsillustrated.cnn.com/2011/writers/peter_king/09/05/laborday/index.html#ixzz1XBwx7L8g