Jackson is second in the NFL with 1,031 yards rushing and 1,262 yards from scrimmage. He says he is day-to-day.
Jackson says he wasn't hurt on any particular play in a 21-13 loss to Arizona on Sunday, describing the injury as "wear and tear of the year."
Rams guard Richie Incognito was restricted to conditioning work and is likely to miss a fourth straight game with a foot injury, while rookie offensive tackle Jason Smith did not pass baseline tests for what coach Steve Spagnuolo termed a mild concussion. Spagnuolo believed Smith would take the test again Thursday.
Copyright 2009 by The Associated Press