I'll give him one more season before writing him off (just because of how important I feel he is to our side). Needs to play 22 games next season with the output he was giving us before going down this year.
No point in holding him past 2013 if he is only going to play half a season again. If he does go down next year with the same ankle/achilles/heel related injury, definitely time to cash in on his currency (or what is left of it).