Andy Lewis/Getty Images

Dak Prescott left Wednesday's practice early after having soreness in his right arm. After undergoing an MRI, it was determined that the Cowboys quarterback is dealing with a muscle strain that will be evaluated on a day-to-day basis. 

The initial fear was that Prescott had an ankle-related setback, according to the Cowboys' official website. The rest of Dallas' first-team reps were handled by backup Garrett GilbertBen DiNucci and Cooper Rush also saw time under center. 

"I felt some soreness when making certain throws today, and I really decided not to push things too far," Prescott said after practice, via David Moore of The Dallas Morning News. "Better to be cautious and smart about it. I don't see this as any kind of serious setback. We'll treat it on a daily basis and I'll be fine." 

Expectations for the 2021 season are sky high for Prescott, who is over nine months removed from surgery to repair the compound fracture to his right ankle. Prior to the injury, Prescott was the NFL's passing leader with 1,856 yards through five games. In just his second game with new head coach Mike McCarthy, Prescott became the first player to throw for 400 yards and run for three scores in the same game. In his last full game under center, Prescott threw for 502 yards and four touchdowns in a Week 4 loss to the Browns

Prescott (who had been full-go in practice prior to Wednesday's setback) recently received praise from former Cowboys Hall of Fame quarterback Troy Aikman. The three-time Super Bowl champion spoke glowingly of Prescott after attending a recent practice. 

"He looked great," Aikman said. "He looked really good. I think every time I see him each year he gets better and better. I know that there is a lot of concern about the ankle and how he's doing there. 

"Heck, it's probably stronger than his other ankle with everything that he has in it. ...I expect him to have an outstanding season."