First and foremost - it was at a House show. How many Wrestlers have suffered stingers, sprains, or non-major injuries and House Shows then played them off to be serious - just to get the fuck outta there?
I know it happens. I've seen it personally. Triple H fell wrong on his head, the match ended suddenly and he just left after being helped to the back. Fucker appeared the next night on Raw in a Main Event match. Obviously not injured.
Second, even if this is a serious injury.. he'd be out, what, 2-4 months max? And its not like he couldn't continue to cut promos, or do the Cutting Edge segment. All in all, with the exception of whatever their plans were for the Tag Team Championships it seems like Edge was becoming irrelevant in the bigger picture to give him a break from it for the previous, oh, 4 years. Much like they've done with Triple H, John Cena, and every other top name in the Company.
Fact is, if you look at whats been happening on the lower table.. Edge has defeated C.M. Punk for the previous, what now, 3 straight weeks? Obviously they were building to an Edge/Punk - Pay per view (possibly Summerslam) showdown. I'm not sure Edge would win or not, but my big guess is.. upon recovering from this possible broken ankle - if its indeed broken - then he'll just come right back into the Heavyweight Championship picture, or a feud with Jericho over Jericho being pissed Edge "lost it for them".
Either way, this is hardly anything to get up-roared about. Edge will be back. Possibly even as soon as next week for the Smackdown tapings. He likely even competes at Night of Champions, with or without a broken ankle.