The Dallas Cowboys will play the Philadelphia Eagles on Sunday in a high-profile game.
McCarthy said that Cooper would start against the Eagles.
During the first week of the season, he injured his thumb and hasn't returned.
It was thought to be the worst-case scenario for the Cowboys when it came to an injury to their quarterback, as he is a two-time Pro Bowler with two seasons of more than 4,000 passing yards on his resume.
He played just five games in 2020 and the team went on to have a poor record.
Rush has started all four of Dallas's games this season and has a perfect record. The team is just one game behind the Eagles after bouncing back from their first loss of the season.
Rush has completed 61 percent of his passes while managing the games and getting the ball into the hands of his teammates.
It has been a successful formula to this point, but the ceiling is higher when the quarterback is under center.
✨ Watch more top videos, highlights, and B/R original contentSince he told reporters last Sunday that he is day-to-day and can hold a football, it's unlikely that he'll play against the Eagles. He would need to make significant strides to be ready to return from his broken thumb in time for the game.
After the injury that required surgery, the Mississippi State product was given a four- to six week timetable for return.
With the backup under center, there is less pressure to get the starter back in time for the important game against the division leaders.