Ever had a bone bruise? I have. Besides being painful, and requiring cortisone injections to alleviate the tenosynovitis that developed, I was advised not to play sport for several weeks due to the risk of permanent damage. Three years down the track, it still causes me problems.
I know a bruise sounds like a piddly thing, and you can mock all you like (hell, would you know what to do with yourselves if you couldn't?), but if they're talking bony injury, it's potentially a few weeks out.