Good move. Hartline has been the number one target for Tannehill this season. The Dolphins will have to throw a lot to keep up with the Saints. Expect him to put up another 20 points in your PPR league.
Foster has been less than stellar this year through three games. This week, he gets Seattle who will shut him down. On top of that, the Texans will most likely be playing from behind, thus throwing the ball at the expense of Foster's carries.
This post was edited on 9/25 at 9:36 pm