ARLINGTON, Texas (AP) — Dallas Cowboys left tackle Tyron Smith is out for a second straight game because of back and groin injuries for a Sunday night NFC East matchup against the NFL-leading Philadelphia Eagles.

Replacements for the four-time Pro Bowler gave up six of Atlanta’s eight sacks in the Falcons’ 27-7 win last week.

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Byron Bell will start over Chaz Green, who replaced Smith against Atlanta and gave up five sacks to Adrian Clayborn. After Green was benched, Bell allowed Clayborn’s franchise-record sixth sack.

The Eagles, with seven straight wins, have a three-game lead on the defending NFC East champion Cowboys and can all but clinch the title with a win.

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Sean Lee had already been declared out for Dallas with a hamstring injury sustained against Atlanta. The Cowboys are 0-2 this season without the 2016 All-Pro linebacker, who missed the earlier games with a hamstring injury as well.

Eagles cornerback Ronald Darby is active after missing eight games because of a dislocated ankle sustained in the opener.

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