LaMichael James out 3-4 weeks

The San Francisco 49ers' rotation at running back gained clarity Friday with news that second-year backup LaMichael James could miss three or four weeks after suffering a sprained MCL in his left knee Thursday night.

The injury, reported by the Sacramento Bee, would remove James from consideration for the first couple weeks of the season. The 49ers open at home against the Green Bay Packers before visiting the Seattle Seahawks in Week 2.

James, a second-round choice in 2012, emerged as a change-of-pace runner behind Frank Gore during the final few weeks of the regular season. The 49ers had lost No. 2 back Kendall Hunter to a torn Achilles' tendon.

There were some questions entering the 2013 season as to where James would fit in the offense with Hunter healthy again. James' injury leaves Hunter as the clear No. 2 runner in terms of carries.

James' injury also could force changes on special teams. James had been getting reps as a punt returner. Wide receiver Kyle Williams, who did not play in the preseason after recovering from ACL surgery, was another candidate for those duties. Williams could be a clearer leading candidate heading into the season.

The 49ers have not provided details regarding James' injury.