since you have sproles, I would hang onto him.
He is still a viable flex since he is a threat for a TD every game. However, Ingram's only hope to really shine is if Sproles gets injured. If Pierre Thomas gets injured, NO will just use Ivory in his place and vice versa.
Personally I was in a similar situation as you last week, and I dropped Ingram for Pierre Thomas last week as a fill-in, I didn't want to see him go but had no other options to drop (had daniel thomas and jackie battle as only other options to drop). I don't think his chances of all of a sudden being too high. But if you have a middle of the run backup WR, I would definitely drop the WR instead.