ALAMEDA, CALIF. - Oakland defensive tackle Richard Seymour missed his second practice in a row Friday, leaving him questionable for Sunday's game against the Vikings.

Seymour has been hampered by a knee injury and has not practiced since Nov. 10. Raiders coach Hue Jackson sounded optimistic earlier this week but backed off that stance slightly Friday.

"Obviously [he's] not where we want him yet," Jackson said. "I feel good about it but we've still got to see."

If Seymour can't play, it would be a huge setback for Oakland's defense. The Raiders are 25th against the run and have the task of trying to slow down Adrian Peterson.

Two other defensive starters are also questionable. Safety Michael Huff (ankle) was downgraded after suffering a setback. Rookie cornerback DeMarcus Van Dyke is still recovering from a hamstring injury.

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