Problem is that Sjax still showed some life last year and he is in the perfect offense for him. Falcons will be relying on him to take the pressure off the passing game and he will also be getting catches. Murray has an injury history also. I would go
Thomas - With Welker around, Thomas will have to share the wealth with him and Decker.
10 team 4 keeper PPR league: (Starters in bold)
RB: A.Peterson. Sproles, Murray (flex), DeAngelo Williams
WR: Julio Jones, Cruz,Garcon, Jeffrey, Douglas, ROyal