Drop Spiller?

[big.d57]

The league is only a 6 team league hence why my team looks really good on paper....I'm debating whether I should drop Spiller. Don't really like his time share but I know he's got potential to be a stud. However, there's some decent RB's on the WW that have me interested.
Should I drop Spiller for any of the following?

Leshoure (had a bye last week)
McGahee (the broncos seem to be relying way more on peyton's arm since they fall into deficits so early)
Steven Jackson (know this guy was a beast in the past, not really sure where he's headed)

QB-Tom Brady
QB-Matthew Stafford
WR-Brandon Marshall
WR-Miles Austin
WR-Reggie Wayne
RB-Trent Richardson
RB-Darren McFadden
TE-Tony Gonzalez
W/R-Jamaal Charles
Bench- Stevan Ridley
Bench-Andy Dalton
Bench- Antonio Brown
Bench-Dez Bryant
Bench-Rashard Mendenhall

[Chaoyi Shih]

you can drop him for S.Jax, but i don't think it will matter anyway.