Not sure exactly what you are looking for, but it sounds like you want fftoday.com
. You can look up stats by week for previous seasons, and you can input your scoring system. They are not actual game logs or box scores, but you can see how players did during a particular week. For example under my local leagues scoring system, I can find out that in week 7 of the 2005 season, Donovan McNabb had 18.3 points and was the 9th highest scoring QB that week.