...cracked ribs heal; back problems can last a lifetime.

I hope this is the extent of the jinx!

They vary a lot from case to case. My Friend had one along her shin but she still ran craws country. They can be more serious though and because it is in the ribs there will probably be a significant amount of pain and I don't think he will be back this week. But I am still hopeful for just a stint on the 15 day DL. BP is great with injuries and they will have a good in depth look at this in the next couple days. I will post it if no one else beats me to it.
This is better then say, a ruptured disk but still not exactly good news.

   Generally speaking, whether it's a contusion(bruise), fracture or as noted stress fracture...these can cause pain for up to 6-8 weeks. The problem with the thoracic area is that with every breath he takes, he will feel discomfort. Ribs and intercostal muscles move with each respiration. Ribs interface with the thoracic vertebrae, and in these types of injuries, the pain can refer to his back.
   As he heals, he can become more active as the discomfort will reduce with each passing week. There are things that can be done to get Crosby fuctional before that 6-8 week window, but factors such as swinging a bat will dictate how much pain he can tolerate.
   Let's hope he's a quick healer!

I mentioned in another thread that I saw Crosby fall hard on his back and do an awkward back summersault during the last week of spring training. He was backpedalling for a pop up at the time. It sure looked like the sort of fall that could cause some injury.

Stress fractures do heal, however, so I guess it's not terribly bad news.

Was Croz having a little too much fun down in AZ, if you know what I mean... :)

but I was relieved to see it, especially after reading the stories in today's papers.

Ribs heal, and then they're fine.  Bad backs are a chronic problem.

Also, on the bright side, Crosby's absence will give the other players (Ellis, Ginter and Scutaro) a chance to show their stuff.  We should have a decent idea who deserves to stay by the time Crosby returns.

could be 4 weeks.  He's young and strong, which will help him way more than any PT.  PT generally won't do anything for this type of injury at first, just time to heal.  The bad news is that if there is damage to the soft tissue or intercostal ligaments, it could linger (as in all season).  That would be more likely in the case of a stress fracture, which I do not believe any more than Jerry Rice's cracked patella was unrelated to his knee surgey (from which his patellar tendon was harvested!)  Two big extenuating circumstances are that he can't do anything to maintaining fitness for at least 3 weeks (again, issue minimized since he's young) and the motion of swinging a baseball bat, especially his swing, will keep sidelined longer than many other activities would.  From what I have read, 6 weeks sounds optimistic - I'd expect 10.