Dallas Cowboys quarterback Andy Dalton (14) is hit by Washington Football Team inside linebacker Jon Bostic (53) in the second half of an NFL football game, Sunday, Oct. 25, 2020, in Landover, Md. Dalton left the field after this hit and Bostic was ejected from the game. (AP Photo/Patrick Semansky)

Dalton left the field after this hit and Bostic was ejected from the game. (AP Photo/Patrick Semansky)FRISCO, Texas – The Dallas Cowboys declared quarterback Andy Dalton out Saturday for their game in Philadelphia because of a concussion, clearing the way for rookie Ben DiNucci's first start. Prescott was the last rookie to start at quarterback for Dallas four years ago. The Cowboys activated linebacker Sean Lee from injured reserve, setting up the veteran for his season debut. The 11th-year player has been out since the start of training camp because of a core muscle injury that required surgery.