Staley also confirmed that wide receiver Mike Williams suffered a high ankle sprain in Sunday's 37-23 loss to the Seattle Seahawks and will miss "weeks, not days."
Jackson was carted off the field in the second quarter Sunday after a play in which Seattle's Marquise Goodwin caught a 23-yard touchdown pass with 1:40 left in the first half. Jackson had coverage but suddenly fell near the goal line and grabbed at his right knee. An air cast was placed on the leg before Jackson was taken off the field.
The 26-year-old has endured a rough season. He underwent ankle surgery in late August and missed the first two games.