Here is something from a Len P article:
"Conventional wisdom holds, of course, that the slate gets wiped clean for the playoffs and that all dozen postseason franchises begin the pursuit of a Super Bowl title from scratch. Technically that is true. In application and in history, however, that isn't necessarily the case. Since the league instituted the 12-team playoff format in 1990, teams that advanced to the playoffs on regular-season winning streaks of three or more games won more than 70 percent of their postseason openers."
Manning is a student of the game, as is Dungy, and both have been in the situation of being able to rest in week 17 and then losing in the first game of the playoffs. I don't think it happens again and that they try to put the game away early.