It depends on the injury you are considering. For example: I fully expect to read about the following tight ends having their knees drained on a regular basis during 2011:
Kellen Winslow - his surgically repaired knee (the one he shredded in the motorcycle accident) has never been quite right since. Pain management techniques and draining are necessary on this chronic and recurring injury (loose bodies in the knee (meaning chips of bone and chunks of cartilage, if there IS still cartilage in there)).
Chris Cooley - he is also having chronic issues with a knee that requires drainage and etc.
I am very comfortable saying that the two guys above (among others) will continue to have injury issues with their knees. Winslow only practices about once a week since arriving in Tampa because the team wants to shield the knee from as much wear-and-tear as possible
I do NOT expect to hear more about the following injuries:
Matthew Stafford and Tony Romo's broken clavicles.
Broken bones generally actually heal more strongly in the area where they were broken due to extra calcification on the bone surfaces (except in the case of very extensive breaks - shattered/spirally broken bones like the leg injury that SEA WR Deon Butler is dealing with).
In the case of other players, who have had repeated problems with a joint but not a degenerative condition, you can generally expect an elevated risk of re-injury, but it isn't as certain as the chronic problems like Winslow's and Cooley's.
Michael Vick's history of problems with his A/C joints (shoulders) is an example of "increased risk".
Go read
THIS (free for anyone, released 7/14) for more discussion and current examples.
MW