BEREA, Ohio -- Cleveland Browns quarterback Case Keenum will get the start Thursday against the Denver Broncos in place of Baker Mayfield, who is battling a torn labrum in his left, non-throwing shoulder and has officially been ruled out.
A limited participant in Tuesday's practice, Mayfield said earlier that day that he planned to start and that it would ultimately be his decision. But Mayfield added that he would play only if he felt that his injury wouldn't hamper the team or his own performance.
"Only I know how my body feels," Mayfield said Tuesday. "If anyone questions whether I am hindering the team and going out there injured, that's just not right. It's my decision. I get to say whether I am able to play or not, and that's just how it is."
Mayfield suffered the shoulder injury Sept. 19 against the Houston Texans while attempting to make a tackle after throwing an interception. He continued to play through it, wearing a harness on the shoulder for support, but aggravated the injury Sunday against the Arizona Cardinals.
A league source told ESPN that Mayfield was advised against playing by both team doctors and his own doctor, Orr Limpisvasti, an orthopedic surgeon for the Anaheim Ducks.
He will miss his first game since taking over the Browns' starting quarterback role in Week 3 of the 2018 season, with his 51 consecutive regular-season starts the fourth-longest active streak among quarterbacks.
A league source told ESPN on Tuesday that the Browns hope Mayfield will avoid season-ending surgery.
"I feel very ready," Keenum said. "I've been ready. You don't have to get ready if you stay ready."
Keenum has been Mayfield's backup since last season. He has appeared in four games with the Browns, completing 6 of 13 passes for 52 yards.
"We have full confidence in him to lead us and do the things necessary to put us in position to win," Browns coach Kevin Stefanski said in a statement Wednesday. "Baker fought really hard to play, he's a competitor and obviously wants to be out there but just couldn't make it on a short week. We know he will continue to do everything in his power to return as quickly as possible."
Mayfield's being ruled out adds to the Browns' injury issues on offense. Cleveland will be without running backs Kareem Hunt and Nick Chubb, who are both battling calf injuries. Wide receiver Odell Beckham Jr. (shoulder) and starting offensive tackles Jack Conklin (knee) and Jedrick Wills Jr. (ankle) did not practice Monday or Tuesday and are listed as questionable on the team's official injury report.
The Browns had opened as a 6-point favorite over the Broncos, but the line is down to Cleveland -3.5 as of Wednesday morning. The over/under has dropped from 44.5 to 41.5.
Mayfield could return as soon as Cleveland's game on Oct. 31 against the Pittsburgh Steelers, if the inflammation goes down and allows the quarterback to return to strengthening the shoulder to stabilize it.