The Argentina international is expected to miss several weeks, leaving 21-year-old Mike Penders in line for an extended run in goal after making his Premier League debut at Hill Dickinson Stadium.
Chelsea confirmed the injury on Sunday, saying further hospital assessment after the collision had revealed a fractured jaw requiring surgery. The club wished Martínez a speedy recovery and pledged to support him during his rehabilitation.
The injury happened midway through the second half as Martínez came out to deal with a set-piece. He collided with Branthwaite and needed lengthy treatment before being carried from the pitch on a stretcher and taken to hospital.
Chelsea manager Xabi Alonso said after the match that Martínez had been conscious when he left the stadium. The goalkeeper subsequently reassured supporters himself, posting a message from his hospital bed.
“Thanks to everyone for the messages. The operation went well,” he wrote. “The most important thing is that we won and kept a clean sheet. We’ll be back in a few weeks.”
His wife, Mandinha, also sought to ease concerns, describing the injury as nothing serious and saying he would soon be back to normal.
The Daily Mail reported that the setback could leave Martínez unavailable for a demanding spell of fixtures, including Premier League meetings with Tottenham Hotspur, Manchester United and Sunderland, as well as a Carabao Cup tie away to Liverpool.
Penders now has an opportunity to establish himself under Alonso. The Belgian joined Chelsea from Genk in 2024 and spent last season on loan at Strasbourg before returning to compete for a place in the senior squad.
He was brought on against Everton after Martínez’s injury and helped Chelsea see out the 2-0 victory, which also delivered the club’s first Premier League clean sheet of the season.
Penders had hoped to challenge for the starting position, but Martínez’s arrival from Aston Villa had appeared to put him behind a more experienced goalkeeper. The circumstances have now brought his chance forward.
Teddy Sharman-Lowe is expected to provide cover as Penders prepares for the next fixtures. Chelsea will hope their young goalkeeper can maintain the defensive stability shown at Everton while Martínez recovers.