It's not gonna happen at a catch weight, Chavez Jr has enough trouble making 160 lbs right now. Plus, most likely Alvarez would win. Chavez Jr has no defense so unlike the Gomez fight, Alvarez would have no trouble landing on him and while Chavez Jr has shown a decent chin against non-punchers that hit him a lot, I doubt he could take the shots of Alvarez as well.
Both can fit quality fights in now for December, and keep this march date. Big step up for both, but bigger for Canelo IMO. I got Chavez by T/KO after 9.:deal