The early word on the street is that Chad Pennington has a dislocated shoulder. Not a torn rotator cuff.
Why is this good news for him?
While a dislocated shoulder may also involve a torn cuff it does not necessarily have to. Both injuries would put Pennington out for several weeks but the dislocated shoulder, sans a cuff tear, will allow Pennington to make an eventual recovery. Probably full.
The rotator cuff is the thin muscle that lies underneath and between your deltoid muscles (shoulders). It is essentially assists in articulating the shoulder and when the arm's range enters certain extreme angles the cuff is more or less on its own, as the deltoids have no role in those positions.
In my opinion the rotator cuff is the biggest design flaw in the human anatomy. It is too small to be expected to suddenly handle what much larger muscles can. Then again, I don't believe that the human body was designed. But that's something else entirely. ;)
Think of doing a bench press. If you touch the bar to your lower pectoral muscle and then push the bar up and back towards your eyes you have done it perfectly. You have used your pectorals, triceps and deltoids and a host of other minor muscles, including the cuff. If the bar goes too far forward, say nearing your ribs, it involves more of the rotator cuffs and increasingly less of your chest, which is the biggest group you were relying on to perform the exercise. The rotator cuffs, as I said before, are very thin and tear easily when suddenly forced to maneuver weights that previously were being sustained by larger muscle groups.
So while this might be Pennington's last start as a Dolphin (and I hope he somehow stays involved with the team - even if Henne proves he's the man) we can all hope for his sake that the separated shoulder does not involve a cuff tear.
He might get back in the game faster with a cuff tear, but given it is his throwing arm the injury will be a nagging one and will forever diminish his arm strength. I've had a tear before. It took me three and a half years to get my shoulder strong enough to go heavy on bench again. I just got back to where I was (benching 350 these days) this month. It has not been an entirely pleasant experience.
Incidentally, I tore it playing football in the snow. My team won though, so it was easier to take. ;)