Due to your ridiculously large roster I would not make this move. You've got enough depth at RB for a rebuild team and you said it yourself, Morris doesn't factor in the passing game whereas Blackmon will likely see a minimum of 8-10 targets a week now with Shorts sidelined for the foreseeable future -- and Jax will be playing from behind which will lead to a lot of nice yardage gains for Blackmon. Now if this were a normal sized roster it would be a little different. However you definitely need help on WR not the other way around.
I'd actually be shopping RGIII and T-Rich from your team to add a little more promising depth to your team. Not that RG and T-Rich aren't great, but do you really want the headache that should already be happening to continue? Someone might spend a lot on either of those players and lets face it, you're not going to contend with this roster. Keep the rebuild going and get rid of some of the players that are more potential headaches than potential superstars compared to the rest of the field.
[SIZE="1"][FONT="Verdana"]10 team Cumulative Points Only - Keep 4
G (3), A (2), +/- (1), PPP (1), PIM (0.25/min), S (0.4), H (0.2), Bs (0.2), FoW (0.1), W (4), Sv (0.2), SO (4), GA (-1)
C - Anze Kopitar, Mike Ribeiro,
LW - Evander Kane, Max Pacioretty, JVR
RW - Tyler Seguin (C/RW), Bryan Little, Jason Pominville
D - Erik Karlsson , Mike Green, Alex Pietrangelo, Sergei Gonchar, Christian Ehrhoff
G - Jonathan Quick , Braden Holtby, Jonathan Bernier