Alright...where are you getting your info from (for your second estimation of time)?? 18 months is about on par..so the guy you quoted is right around the time frame with his lowest and your about on point with your highest.. Some one tears up his knee in season and has surgery in the off-season..if he is 'ready' by the next season that player normally doesn't have full speed and burst until the following season when he is truly 100% at full strength. This is at least what I have noticed with RBs. And of course everyone heals at different rates.