Claudio Bravo's season could be over after the Manchester City goalkeeper was taken off on a stretcher in Thursday's Manchester derby with a calf injury.
And that would give Willy Caballero, who is out of contract at the end of the season, a last opportunity to earn a new deal by impressing in City's final five Premier League matches of the season as they try to secure a top-four place.
Bravo picked up the injury in the 79th minute of the 0-0 draw with Manchester United after hurting himself while catching a cross and clearing the ball.
City are still assessing the Chile international but manager Pep Guardiola fears he will miss the remaining three weeks of the season.
"Of course he has an injury, probably for some weeks," Guardiola told a news conference after the game. "I don't know if he will be available again this season."
Bravo only returned to City's starting lineup on April 8 after being dropped, with Caballero starting the previous 10 Premier League and Champions League matches.
Bravo has struggled since moving to the Etihad Stadium from Barcelona in a £17 million deal in August.
But a source has told ESPN FC that he is determined to fight for his future at City despite speculation that the club are set to bring in a new goalkeeper in the summer.
Sunderland's Jordan Pickford has been watched by the club, a source has told ESPN FC, while Benfica's Ederon Moraes has also been linked with a move to the Etihad Stadium.
Caballero, who joined from Malaga in 2014, comes to the end of this three-year contract in the summer, but City are waiting until the end of the season before deciding on new extensions for their six first-team players whose deals are due to run out.
Bravo is not the only doubt for City's game at Middlesbrough on Sunday, with John Stones still fighting to recover from a muscular injury while captain Vincent Kompany has played every minute of the club's last three matches.
David Silva also hopes to be back after missing the draw with United, while Gabriel Jesus will be pushing for a start after being used as a late substitute.