Buffalo Bills coach Rex Ryan says he's taking the approach that running back LeSean McCoy will not play against Dallas on Sunday because of an injured right knee.

Ryan provided the update after McCoy missed his second straight practice on Thursday. McCoy was hurt in a 35-25 loss at Washington last weekend, and it's uncertain whether he can return for Buffalo's season finale against the New York Jets on Jan. 3.

Starting tight end Charles Clay did not practice because of a back injury that prevented him from playing last weekend. Rookie starting cornerback Ronald Darby's status is uncertain after he missed practice because of a groin injury.

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The Bills (6-8) and Cowboys (4-10) have both been eliminated from playoff contention.