The Carolina Panthers have placed quarterback Sam Darnold on injured reserve due to a shoulder issue that could keep him out for a minimum of four weeks.

Darnold is thought to have sustained the injury last Sunday as the Panthers were beaten 24-6 by the New England Patriots.

The 24-year-old picked up a shoulder problem - believed to be separate from his latest issue - and sustained a concussion against the Atlanta Falcons the previous week, but was passed fit to face the Patriots.

An MRI scan revealed an incomplete fracture on the scapula of the quarterback's right shoulder, but he played through the injury in the eventual defeat.

"You look at the second half, he obviously was playing with something," Panthers coach Matt Rhule said earlier this week.

Darnold will now be replaced by P.J. Walker, who joined the Panthers last year and is set for his second NFL start against the Arizona Cardinals.

Walker played college football at Temple and was coached by Rhule, who insisted that the 26-year-old is where he is on merit and because of the ability he has shown.

He was signed as an undrafted free agent by the Indianapolis Colts in 2017 but did not feature for them before eventually joining the Houston Roughnecks in the XFL two years later, before moving to Carolina in 2020.

"P.J. is here because I believe in him," Rhule said.