Karlsson is without question one of the top 3 fantasy D in the entire league...and that's being generous [most consider him the best].
Is Smith even a top 10 G? I'm not so sure.
Is Landeskog even a top 20 F? Nope.
Is Leddy even a top 30 D? No!
You give up lots of players and get the single-best one back...by a HUGE margin. The fact that Karlsson is so affordably priced makes this robbery in your favor as you gain the best player and salary cap relief.
Congratulations!
10 Team [keep 10 + 4 prospects]
Scoring F=1[g/a]; D=2[g], 1[a]; G=2[w], -1[L], 1[OT], 2[SO] Top 12 F, 6 D, 2 G count
Forwards
Crosby, Ovechkin, Backstrom, Wheeler, Byfuglien, Hornqvist, Simmonds, Ladd, Zuccarello, Ribeiro, Desharnais, Semin, MacArthur, Moulson, Purcell, Soderberg, Dupuis
Defense
Keith, Goligoski, Carlson, Krug, Trouba, Streit, Pouliot, Ceci, Nurse, Martinez
Goalie
Fleury/Price/Rask