Manning has been eating up the blitz all season -- going into today, he had 8.9 yards per pass attempt, 9 TDs (plus one rushing), one INT, a 121 passer rating and only four sacks out of 59 blitzes.
The teams that have stopped the Colts this year have done it with very little blitzing, pressure or sacks -- only two sacks and two hurries COMBINED in three games by the Jags (14 points allowed), Titans (14 points allowed) and Bills (17 points allowed). You might blitz every now and then to try to surprise him and get a big play, but if you're going to blitz, blitz, blitz, you're also going to pay, pay, pay.