The Cowboys lost starting quarterback Dak Prescott to a broken ankle last year in Week 5 against the New York Giants, but it’s a new shoulder injury that might delay his readiness for the start of the season against the Bucs. Prescott recovered from his season-ending ankle injury this offseason and was participating in training camp until leaving Wednesday’s practice with soreness in his throwing shoulder.

The Super Bowl champion Bucs will host the Cowboys at Raymond James Stadium on Thursday, September 9 in a nationally televised game on NBC.

Dallas revealed that an MRI of Prescott’s right shoulder revealed a muscle strain and the team is taking a “purely precautionary” approach. ESPN’s Todd Archer reports that Prescott has a latissimus strain in his throwing shoulder. The Cowboys have embarked on a treatment plan and the team’s doctors and trainers will monitor how Prescott responds on a day-to-day basis.

“I felt some soreness when making certain throws today, and I really just decided not to push things too far,” Prescott said in a statement released by the Cowboys from training camp. “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.”

Prescott was kept out of team drills during the team’s Wednesday practice, and it is unclear when he will be able to return to practice as a full participant.

CowboysWire.com has reported that the shoulder injury could keep Prescott out of action for weeks.

Prescott led Dallas to a 2-3 start last year before his ankle injury. The Cowboys finished Mike McCarthy’s first season in Dallas with a 4-7 record and had to turn to Andy Dalton, Garrett Gilbert and Ben DiNucci to start games down the stretch. Dalton left for Chicago in free agency. That leaves Gilbert, DiNucci and Cooper Rush as the available quarterbacks in Dallas behind Prescott.

Prescott isn’t the only Cowboy dealing with an injury in camp. Pro Bowl pass rusher DeMarcus Lawrence is on the PUP list, as are rookie defensive lineman Chauncey Golston and star wide receiver Amari Cooper, who is recovering from ankle surgery.