To that I would add, how are you doing in your league? If you are comfortably positioned to make the playoffs (up to you to decide that) then go with Knox. If you are looking for someone to give you points right now, go with Freiermuth, since Knox may not play this week.
Personally, I'm willing to gamble that Ebron doesn't impact Freirmuth that much, short or long term. But I'm just a random guy on a fantasy football forum who has never been an Ebron fan. (Yet lost when he had a multiple TD game. Go figure!) But long term, I would still roll with Knox.