Edelman - He is starting to fade some, I know Amendola is out, but Gronk is back as well. Not a bad play, but not jumping up and down.
Decker - I am in the corner of always start your Bronco WR's. Anyone of them can go off and I'd hate to see them do it on the bench. Decker has caught at least 5 passes in every game since week 1. IMO he has to be in your line-up.
Smith - Pitt is still tough against opposing WR's in fantasy. This always seems to be a slug fest with the Ravens. I would stay away from Smith if you have better options and I think you do.
Nicks - Great match up and Nicks seems to be more involved in the offense over the last 3 weeks. The Vikes give up the 4th most points to WR's in the league. Looks like a great week to have him in your line-up.
I would go with Decker and Nicks. I would then rank Edelman 3rd and Smith 4th this week.
Hope this helps.