Why is Joseph Addai rated higher then Brian Westbrook?

Question

This is in regard to fantasy football.

Answer 1

While Brian Westbrook is almost definitely the better back, the wide-open Colts offense with Peyton Manning at the helm forces defenses to guard against the pass very heavily, which leaves Addai to pick up major points. That said, which one is higher rated depends on your league's scoring, as Westbrook will probably have better receiving stats.

Answer 2

That might change by the beginning of the season, since the Colts may lose their veteran center (Jeff Saturday) to a season-ending knee injury.

Answer 3

Younger and healthier in a more prolific offense.