While it can be done, it's not doable without really cheaping out and becoming weaker in other areas. Not only do you have to trade a goalie (which is in everyone's best interest anyway no matter which one gets traded), you'd have to compliance buyout or trade Ballard and Booth, and most likely let Raymond walk, hope that Kassian is ready to handle a top 6 role, and hope that Tanev doesn't get north of $2M. You also have to fill out your roster with players on ELC's or veteran players under $1M a piece, including 6D, so forget about having a solid 3 pairings on D. No other moderate to big signings allowed.
You're essentially trading Booth, Ballard and Raymond for Roy. While I'm sure some people would do that, does it ultimately make sense to tie up $5M in a 3C, be it Kesler or Roy? Raymond is a speedster who would be on a 20g 20a pace over 82 games, and while Booth slumped this year he's usually in the 20-30 goal range. I still think they find a 3C that will make half of what Roy is going to want.