There is not only ONE LJ, that sounds like frigging highlander...there can only be one.
There is always a RB who takes the place of an injured starter and is incredibly influential OR enough to decide a fantasy championship. For starters, LJ has done it two years in a row basically and McGahee before him (although LJ last year was an extreme situation).
I have had all three in all three years and all three have helped me, so to the originally poster, if you can pick up Turner I'd recommend it. However, don't pick him up if there are people who can get you points now. If you want, try and deal two above average players from situation where you have depth and can afford one loss for an influential stud to create room.
There was already a thread on the RBs with most potential to blow up this year, Turner, Maroney, Norwood, Jacobs, etc.
but one thing that I believe wasnt discussed was likelihood of starter getting injured factoring into equation. THEY CALL CAN GET INJURED, but but Dunn is old an dhas a history of going down and Dillon( one person mentioned this) was banged up allt he time last year, so Norwood or Maroney make more sense than Turner probably if they are still on the wire. Turner though is ready, and not just because of a 70 yard run like someone mentioned so why not take a flyer on him if you can.
He who would trade liberty for some temporary security, deserves neither liberty nor security.
Should be applied to our current global situation and fantasy football as well.