Tyron Smith has been a huge reason why DeMarco Murray has been able to get out to such a fast start this season.

But the Cowboys' left tackle has apparently been slowed this week due to an ankle injury sustained during the team's win over Seattle this past Sunday. According to the Fort Worth Star-Telegram, Smith left practice after participating in individual drills to have an MRI on his ankle.

That's not a good sign, though it could just be precautionary. The last thing the Cowboys need is an injury to Smith, who was named the NFC Player of the Week — a rare feat for an offensive lineman. The Cowboys will be without right tackle Doug Free for a few weeks, so having Smith available is ever-important.

Speaking of Murray, he was also absent from Wednesday's practice due to an illness.

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