Baker Mayfield will miss his first career NFL start on Thursday thanks to a torn labrum that'll likely require offseason surgery. But the Browns quarterback might miss plenty more before returning to the lineup. In addition to the torn labrum, Mayfield is also dealing with a fractured humerus bone in his non-throwing shoulder, Fox Sports' Jay Glazer reported Thursday.

Scans this week revealed the fracture, which occurred when his shoulder popped out during the Browns' Week 6 loss to the Cardinals, per Glazer. The break is preventing Mayfield from fully using his rotator cuff when throwing the ball, and the quarterback -- despite attempts this week to suit up for Thursday night's game against the Broncos -- is clear he won't rush back from the fracture.

"I need that fracture to heal for me to get back out there," Mayfield told Glazer.

It's unclear just how long that will take. Cleveland Clinic, for example, notes that most nondisplaced shoulder fractures "require immobilization in a sling" -- a process that can itself last for weeks. Other athletes who have suffered fractured shoulders have been sidelined for months at a time, though rehabilitation schedules can be altered depending on if surgery is part of the process.

A trip to injured reserve could be possible, which would guarantee Mayfield is sidelined at least three games.

In his absence, the Browns are turning to veteran journeyman Case Keenum, who's logged starting experience with the Broncos, Vikings and Washington Football Team among others.