Lynch is a must-start even against the 49ers defense. I'd go with Green for your RB2, he's been playing well and the Rams will definitely be more concerned about stopping Rodgers after his 6 TD game last week.
QB: Matthew Stafford, Colin Kaepernick
RB: Ray Rice, Trent Richardson, Doug Martin, BenJarvus Green-Ellis
WR: Brandon Marshall, Marques Colston, Hakeem Nicks, Percy Harvin
TE: Aaron Hernandez, Brandon Myers
K: Lawrence Tynes