Crohn's Disease can vary alot in severity depending on when it is diagnosed and how well it is treated.
My wife has it. Initially she simply had to take regular medication. Unfortunately she was allergic to some of the regular stuff and now has to go in every 8 weeks for infusions along with daily meds.
At some point as it progresses, Crohn's almost always involves some surgery to remove effected parts of the intestine.
If it's something that he has under control and is dilligent in his medication it shouldn't effect his football career at all.
If it's out of control or he doesn't stay on top of it, he could be in and out of the hospital every time it flares up.
[ Edited by wadjay on Mar 11, 2010 at 10:19 AM ]