He was given three carries and a pass target on those seven snaps — it's not like he was brought in to block. He managed 5 yards on those three carries and completely failed to stay engaged on his target — he didn't even turn his head around.
The other problem is how long can you put Ellington on the field before you worry that he's going to get injured. He's constantly injured even though he's never used.
Too much trouble. Larry Fitzgerald was one of the best players in football for an extended period before we thought we were seeing a drop-off. Ellington was pretty good for a handful of games. Today he's had far more injured/bad games than good ones.