New on SI: Cowboys QB Andy Dalton Ruled Out vs. Eagles, Rookie Ben DiNucci to Start

Dalton was diagnosed with a concussion after he was hit in the head in last week's game.

The Cowboys have downgraded quarterback

Andy Dalton from doubtful to out for Sunday night's game against the Eagles.

Dalton exited last weekend's matchup with Washington after a helmet-to-helmet hit from linebacker Jon Bostic. He was hit in the head as he slid to the ground and later diagnosed with a concussion.

Dalton was replaced by rookie Ben DiNucci, who will make his first career NFL start on Sunday. Garrett Gilbert will be DiNucci's backup against the Eagles. The Cowboys signed Gilbert off the Browns' practice squad on Oct. 13.

Dinucci, a seventh-round pick out of James Madison, is the third quarterback to play for Dallas this season. Starting quarterback Dak Prescott is out for the year after fracturing his ankle against the Giants on Oct. 11. 

The Cowboys and Eagles are set to play at 8:20 p.m. ET in Philadelphia on Sunday night.