Who to drop for playoffs?

I have, over the weeks, built quite the line up. My team that started 0-3 is now 8-3 and with one more win I should clinch a playoff spot.

With that, I need to do a little bit of planning ahead and would like to drop a few bench/flex guys to free up space for additional QBs/DST

  1. Is Sea DST worth holding? They have been hit with some injuries, and while they have been great for 10/11 weeks it may be time to move on

  2. At RB, I have D. Murray, D. Lewis, S. Perine, A. Kamara, and D. Williams.
    I feel most comfortable dropping Williams, who else is droppable? (this is a 12 team 0.5ppr)

  3. At WR: JuJu Smith, AJ Green, D Adams, J Crowder, M Crabtree
    I dont feel like dropping anyone of these, but I would lean towards crowder because I havent started him and I dont know that I will in the next few weeks.

Right now, at QB I have Rivers and Mariota - I might pick up Tyrod because he has a nice schedule for rest of season