Many writers/"experts" will simply point to Manning's unbeaten record against Rex Ryan (at least when he plays the whole game) and pick the Colts to win with confidence. However, this year's Colts team is a depleted as ever from injuries, leaving Manning one of the only consistencies on the team (who has had his own share of hiccups this season). The running game in Indaniapolis, while recently revived, has been nearly non-existient this season.
Let's look at how you attack the Jets defense. Teams with the most success moving the ball on the Jets this season (relative to talent) have been Chicago, New England, Houston, Pittsburgh, and i'll throw in Cleveland and Detroit. All of these teams had some success running the ball against the Jets.
Now, here's some example of teams that the Jets have shut down this season: Miami, Buffalo, Baltimore, Cincinnati, and Green Bay. None of these teams had success on the ground against the Jets.
Notice a trend? The Jets thrive against one-dimensional teams. Manning was able to overcome his so-so running game last year with Dallas Clark, who is on IR. Kansas City, on the other hand, is the best statistical running team in the NFL, and have enjoyed offensive balance throughout most of the season.
On the other side of the ball. the Jets have proved they can run against some of the best run defenses in years. In the past, Dwight Freeney and Robert Mathis, the two best defensive players for Indy, have been mostly neutralized by the Jets' pair of offensive tackles. Sanchez had a strong game throwing the ball in last years AFC title game.
Who would you rather face? Kansas City or Indianiapolis?