This appears to be similar to, if not the exact same, injury
Steve McNair suffered thru last year.
And it was a big deal.
If you've ever hurt your back, you never realized how much you use it until it's hurt.
Nobody (including me) has access to the "real", medical nature of McNabb's injury.
But a QB with a chest injury has a serious problem, IMO.
And if similar to McNair's, he will be in pain and limited for weeks.