At least not according to coach Bruce Arians, who told reporters, per ESPN.com: "I think Andre will continue his same role. We'll keep him healthy and let him continue to develop as a player, but the nice thing David can do is he can do everything Andre does, so you don't have to change if there was an injury."
That didn't pan out. Ellington's pass-catching ability out of the backfield is saucy, but the third-year runner is too small -- at 5-foot-9 and 199 pounds -- to slam the ball between the tackles. His 201 carries last season produced just 660 yards at 3.3 yards per clip.
Johnson will help, giving Arizona a 6-foot-1, 224-pounder with 4.50 speed and the talent to catch passes out of the backfield.
After the Adrian Peterson trade never went down, Johnson was a smart pick that should shore up a running game that let Arizona down last season.