Buffalo Bills running back Fred Jackson 
has began rehabilitating his injured knee last week. With him on the sidelines, RB C.J. Spiller has played exceedingly well. Jackson was expected to be the team's leading rusher and RB1 this season yet that likely won't be the case upon his return. Jackson sprained his LCL in Week 1 and could be out for another three to four weeks.
Fantasy Analysis:
Spiller already has 292 rushing yards and three scores along with five receptions for 72 yards. The Bills can't sit that kind of production and whenever Jackson returns, he'll have to take a backseat to the dynamic third-year back out of Clemson. Jackson missed the final six weeks of the 2011 season and is already injured again. He's 31 years old and in very limited action in Week 1, he had only 15 rushing yards on six carries. Upon his return, Jackson's role will need to be redefined to compliment Spiller.
