"Joe has been outstanding," Eriksson told City's website. "I think we are spoiled with the keepers we have at this club, and we are coming to expect that he is playing as well as he is.
"He is in fantastic form at the moment, and he is spoiling us because we think the way he is playing now is normal! Some of his saves against Liverpool were incredible."
He added: "He's matured as a player and as a person this year and in the future I think he will be a real leader. He already is one, in some ways, but it's not easy to be one in your first full season playing in the Premier League, and he's just 21 years old still.
"It's been an excellent year for him, he's a great talent and is already a very good player - and, of course, he will only get better and better."