Saints don’t think Mark Ingram will be 100 percent when camp starts
If Tusk could pick up the Blitz and Catch AND stay healthy (hopefully he continues to improve here, I love the guy), he would be an amazing back (and probably would have been drafted). He does have a niche on the Saints because of the things he does do well (i.e. hit guys so they feel like they kissed a freight train), not to mention depth.
PT is our best all around back. Sproles is simply incredible. Ingram/Ivory fill different needs, and in their own ways, have made our backfield the envy of many a team.