Arsenal hero Paul Merson is unimpressed with on loan shot stopper David Raya.
The Spaniard has been made the club's new no.1 by boss Mikel Arteta, having arrived from Brentford in the summer.
However, Merson believes that replacing Aaron Ramsdale with Raya in recent games has not been a success.
Speaking to Sky Sports, Merson said: "I'm a great believer in not fixing something that isn't broken.
"With his handling of the goalkeeper situation, Mikel Arteta has put everyone under severe pressure.
"He's put himself under pressure and he's put David Raya under pressure.
"That was another major, major mistake at Stamford Bridge."