ASHBURN, Va. -- Redskins wide receiver DeSean Jackson said Wednesday that missing most of the preseason could have contributed to the hamstring injury he suffered in the first quarter of a season-opening loss.

Jackson, who sustained a sprained joint in his right shoulder during an Aug. 6 practice, missed all four of Washington's preseason games. He returned to the practice field the week before the Dolphins game, but lasted just two offensive series last Sunday before sustaining a partial hamstring tear that was discovered in an MRI on Monday. He is expected to miss three to four weeks.

Jackson was attempting to break free from Miami cornerback Brent Grimes on a deep pattern when he felt the muscle pop. He hobbled to the sideline and didn't return, calling it "scary because my legs and my speed is what I do good at.

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