Former Gunners captain Henry has been linked with a return to England at Manchester City.
"Personally I found him quite sharp playing for France against Austria and Serbia," said Wenger. "There's tough competition up there [Barcelona] but I believe he should play through the centre where he feels more comfortable because it's more difficult to be a winger when you are over 30.
"I want him to be happy first of all because he made us happy at Arsenal for many years and at the moment he is not. But unfortunately that's part of the career of a player. He goes through these kinds of periods at the start of his career and at the end of his career.
"But I feel at the moment that he is too young to be at the end of his career."