The Swede scored in last night's friendly win over Vancouver Whitecaps.
"John is young. He is a good player and I think he can have a good future at Manchester City," said Barry.
"He is strong. He is a typical English striker, even though he is Swedish. He has a good technique. He wants to improve.
"He will have time here. It is important that he continues to work well and continues to improve.
"Today he scored a good goal but when you are a young player, you need to improve every day. This year is important. He has a chance."