Basically recoup the picks lost in the Hamonic trade (though likely pushed back a bit as Toronto will finish higher, and maybe get a 2018 2nd back as well) and when you look at it they swap out a younger RHD on a good contract for 3 more years after this one for a slightly older RHD on a very good deal for 2 more seasons after this one. Plus they get a potential stud winger that they can manage the contract of.
TOR:
D.Hamilton
F.Hamilton
NYI:
2018 1R, 2R
2019 or 2020 2R
CGY:
Hamonic
Marner (RFA 2019) or Nylander (RFA 2018)
2018 1R, 2R
2019 or 2020 4R
I think I got the picks right