This news doesn't seem to be too big as the move was kind of expected and more procedural. Foster, coming off an Achilles' tear, will look to get himself ready to practice and when he does, it is expected that he'll be running with the starters. He's worth a shot in drafts this year as he is still one of the more talented backs in the league. Health has been the major issue, not talent.
After rumors all offseason that the Eagles were looking to part ways with Sproles, this extension says otherwise. While he may have lost a small step since his prime days in New Orleans, Sproles still has a skill set that is coveted today. Expect him to be the pass-catching back for the Eagles under new Head Coach Doug Pederson and play a solid role in their offense. He's a decent flex in PPR leagues and less desirable in standard leagues. You know the drill.